feat: implement bff layer

app/books/bbd/page.tsx

@@ -60,7 +60,6 @@ export default async function BbdPage() {
                           </p>
                         </div>
                         <span className="text-sm text-muted-foreground sm:shrink-0 sm:ml-4">
-                          {seg.paragraphs.length} paragraphs
                         </span>
                       </Link>
                     </li>

app/books/bk/[chapter]/page.tsx

@@ -162,14 +162,7 @@ function SidebarLink({
   item: BkSidebarItem;
   isActive: boolean;
 }) {
-  let label: string;
-  if (item.type === "chapter" && item.chapter != null) {
-    // Extract just the title portion after "Chapter N: "
-    const titlePart = item.label.replace(/^Chapter \d+:\s*/, "");
-    label = `${item.chapter}. ${titlePart}`;
-  } else {
-    label = item.label;
-  }
+  const label = item.label;
 
   return (
     <Link

app/books/bs/page.tsx

@@ -118,7 +118,6 @@ export default async function BsPage() {
                           {introduction.title}
                         </p>
                         <span className="text-sm text-muted-foreground sm:shrink-0 sm:ml-4">
-                          {introduction.paragraphs.length} paragraphs
                         </span>
                       </Link>
                     </li>
@@ -133,7 +132,6 @@ export default async function BsPage() {
                           {foreword.title}
                         </p>
                         <span className="text-sm text-muted-foreground sm:shrink-0 sm:ml-4">
-                          {foreword.paragraphs.length} paragraphs
                         </span>
                       </Link>
                     </li>

app/books/cbhc/[chapter]/page.tsx

@@ -162,14 +162,7 @@ function SidebarLink({
   item: CbhcSidebarItem;
   isActive: boolean;
 }) {
-  let label: string;
-  if (item.type === "chapter" && item.chapter != null) {
-    // Extract just the title portion after "Chapter N: "
-    const titlePart = item.label.replace(/^Chapter \d+:\s*/, "");
-    label = `${item.chapter}. ${titlePart}`;
-  } else {
-    label = item.label;
-  }
+  const label = item.label;
 
   return (
     <Link

app/books/ds/page.tsx

@@ -63,7 +63,6 @@ export default async function DsPage() {
                           </p>
                         </div>
                         <span className="text-sm text-muted-foreground sm:shrink-0 sm:ml-4">
-                          {seg.paragraphs.length} paragraphs
                         </span>
                       </Link>
                     </li>

app/books/ej/page.tsx

@@ -63,7 +63,6 @@ export default async function EjPage() {
                           </p>
                         </div>
                         <span className="text-sm text-muted-foreground sm:shrink-0 sm:ml-4">
-                          {seg.paragraphs.length} paragraphs
                         </span>
                       </Link>
                     </li>

app/books/ek/page.tsx

@@ -60,7 +60,6 @@ export default async function EkPage() {
                           </p>
                         </div>
                         <span className="text-sm text-muted-foreground sm:shrink-0 sm:ml-4">
-                          {seg.paragraphs.length} paragraphs
                         </span>
                       </Link>
                     </li>

app/books/gg/[chapter]/page.tsx

@@ -217,14 +217,7 @@ function SidebarLink({
   item: GgSidebarItem;
   isActive: boolean;
 }) {
-  let label: string;
-  if (item.type === "chapter" && item.chapter != null) {
-    // Extract just the title portion after "Chapter N: "
-    const titlePart = item.label.replace(/^Chapter \d+:\s*/, "");
-    label = `${item.chapter}. ${titlePart}`;
-  } else {
-    label = item.label;
-  }
+  const label = item.label;
 
   return (
     <Link

app/books/gg/page.tsx

@@ -64,7 +64,6 @@ export default async function GgPage() {
                           </p>
                         </div>
                         <span className="text-sm text-muted-foreground sm:shrink-0 sm:ml-4">
-                          {seg.paragraphs.length} paragraphs
                         </span>
                       </Link>
                     </li>
@@ -126,7 +125,6 @@ export default async function GgPage() {
                           </p>
                         </div>
                         <span className="text-sm text-muted-foreground sm:shrink-0 sm:ml-4">
-                          {seg.paragraphs.length} paragraphs
                         </span>
                       </Link>
                     </li>

app/books/hkh/page.tsx

@@ -60,7 +60,6 @@ export default async function HkhPage() {
                           </p>
                         </div>
                         <span className="text-sm text-muted-foreground sm:shrink-0 sm:ml-4">
-                          {seg.paragraphs.length} paragraphs
                         </span>
                       </Link>
                     </li>

app/books/iso/[mantra]/page.tsx

@@ -50,8 +50,11 @@ export async function generateMetadata({
   const isVerse_ = content && "mantra" in content && "devanagari" in content;
   const paragraphs = content
     ? isVerse_
-      ? [(content as IsoVerse).translation, ...(content as IsoVerse).purport]
-      : (content as IsoIntroSegment).paragraphs
+      ? [
+          (content as unknown as IsoVerse).translation,
+          ...(content as unknown as IsoVerse).purport,
+        ]
+      : (content as unknown as IsoIntroSegment).paragraphs
     : undefined;
 
   const quote = extractQuoteFromHl(sp, paragraphs);
@@ -64,7 +67,7 @@ export async function generateMetadata({
   }
 
   const title = isVerse_
-    ? `${(content as IsoVerse).reference}: ${(content as IsoVerse).title}`
+    ? `${(content as unknown as IsoVerse).reference}`
     : content && "title" in content
       ? (content as IsoIntroSegment).title
       : `Mantra ${slug}`;
@@ -110,7 +113,7 @@ export default async function IsoMantraPage({
           {verse && (
             <>
               <span className="text-primary">{verse.reference}: </span>
-              {verse.title}
+              {verse.bookTitle}
             </>
           )}
           {intro && intro.title}

app/books/iso/page.tsx

@@ -68,7 +68,6 @@ export default async function IsoPage() {
                           </p>
                         </div>
                         <span className="text-sm text-muted-foreground sm:shrink-0 sm:ml-4">
-                          {frontPages.paragraphs.length} paragraphs
                         </span>
                       </Link>
                     </li>
@@ -85,7 +84,6 @@ export default async function IsoPage() {
                           </p>
                         </div>
                         <span className="text-sm text-muted-foreground sm:shrink-0 sm:ml-4">
-                          {introduction.paragraphs.length} paragraphs
                         </span>
                       </Link>
                     </li>
@@ -164,7 +162,6 @@ export default async function IsoPage() {
                         </p>
                       </div>
                       <span className="text-sm text-muted-foreground sm:shrink-0 sm:ml-4">
-                        {aboutAuthor.paragraphs.length} paragraphs
                       </span>
                     </Link>
                   </li>

app/books/kb/[volume]/page.tsx

@@ -72,7 +72,6 @@ export default async function KbVolumePage({
                           </p>
                         </div>
                         <span className="text-sm text-muted-foreground sm:shrink-0 sm:ml-4">
-                          {seg.paragraphs.length} paragraphs
                         </span>
                       </Link>
                     </li>
@@ -106,7 +105,6 @@ export default async function KbVolumePage({
                         </p>
                       </div>
                       <span className="text-sm text-muted-foreground sm:shrink-0 sm:ml-4">
-                        {ch.paragraphs.length} paragraphs
                       </span>
                     </Link>
                   </li>

app/books/lcl/[chapter]/page.tsx

@@ -221,14 +221,7 @@ function SidebarLink({
   item: LclSidebarItem;
   isActive: boolean;
 }) {
-  let label: string;
-  if (item.type === "chapter" && item.chapter != null) {
-    // Extract just the title portion after "Chapter N: "
-    const titlePart = item.label.replace(/^Chapter \d+:\s*/, "");
-    label = `${item.chapter}. ${titlePart}`;
-  } else {
-    label = item.label;
-  }
+  const label = item.label;
 
   return (
     <Link

app/books/lcl/page.tsx

@@ -64,7 +64,6 @@ export default async function LclPage() {
                           </p>
                         </div>
                         <span className="text-sm text-muted-foreground sm:shrink-0 sm:ml-4">
-                          {seg.paragraphs.length} paragraphs
                         </span>
                       </Link>
                     </li>
@@ -126,7 +125,6 @@ export default async function LclPage() {
                           </p>
                         </div>
                         <span className="text-sm text-muted-foreground sm:shrink-0 sm:ml-4">
-                          {seg.paragraphs.length} paragraphs
                         </span>
                       </Link>
                     </li>

app/books/lob/page.tsx

@@ -60,7 +60,6 @@ export default async function LobPage() {
                           </p>
                         </div>
                         <span className="text-sm text-muted-foreground sm:shrink-0 sm:ml-4">
-                          {seg.paragraphs.length} paragraphs
                         </span>
                       </Link>
                     </li>

app/books/mg/page.tsx

@@ -60,7 +60,6 @@ export default async function MgPage() {
                           </p>
                         </div>
                         <span className="text-sm text-muted-foreground sm:shrink-0 sm:ml-4">
-                          {seg.paragraphs.length} paragraphs
                         </span>
                       </Link>
                     </li>

app/books/mm/page.tsx

@@ -116,7 +116,6 @@ export default async function MmPage() {
                         {introduction.title}
                       </p>
                       <span className="text-sm text-muted-foreground sm:shrink-0 sm:ml-4">
-                        {introduction.paragraphs.length} paragraphs
                       </span>
                     </Link>
                   </li>

app/books/mog/page.tsx

@@ -60,7 +60,6 @@ export default async function MogPage() {
                           </p>
                         </div>
                         <span className="text-sm text-muted-foreground sm:shrink-0 sm:ml-4">
-                          {seg.paragraphs.length} paragraphs
                         </span>
                       </Link>
                     </li>

app/books/nbs/page.tsx

@@ -116,7 +116,6 @@ export default async function NbsPage() {
                         {introduction.title}
                       </p>
                       <span className="text-sm text-muted-foreground sm:shrink-0 sm:ml-4">
-                        {introduction.paragraphs.length} paragraphs
                       </span>
                     </Link>
                   </li>

app/books/nod/[chapter]/page.tsx

@@ -203,14 +203,7 @@ function SidebarLink({
   item: NodSidebarItem;
   isActive: boolean;
 }) {
-  let label: string;
-  if (item.type === "chapter" && item.chapter != null) {
-    // Extract just the title portion after "Chapter N: "
-    const titlePart = item.label.replace(/^Chapter \d+:\s*/, "");
-    label = `${item.chapter}. ${titlePart}`;
-  } else {
-    label = item.label;
-  }
+  const label = item.label;
 
   return (
     <Link

app/books/nod/page.tsx

@@ -70,7 +70,6 @@ export default async function NodPage() {
                           </p>
                         </div>
                         <span className="text-sm text-muted-foreground sm:shrink-0 sm:ml-4">
-                          {seg.paragraphs.length} paragraphs
                         </span>
                       </Link>
                     </li>

app/books/noi/page.tsx

@@ -65,7 +65,6 @@ export default async function NoiPage() {
                           </p>
                         </div>
                         <span className="text-sm text-muted-foreground sm:shrink-0 sm:ml-4">
-                          {frontPages.paragraphs.length} paragraphs
                         </span>
                       </Link>
                     </li>
@@ -82,7 +81,6 @@ export default async function NoiPage() {
                           </p>
                         </div>
                         <span className="text-sm text-muted-foreground sm:shrink-0 sm:ml-4">
-                          {preface.paragraphs.length} paragraphs
                         </span>
                       </Link>
                     </li>
@@ -141,7 +139,6 @@ export default async function NoiPage() {
                         </p>
                       </div>
                       <span className="text-sm text-muted-foreground sm:shrink-0 sm:ml-4">
-                        {appendixes.paragraphs.length} paragraphs
                       </span>
                     </Link>
                   </li>

app/books/ochkm/page.tsx

@@ -60,7 +60,6 @@ export default async function OchkmPage() {
                           </p>
                         </div>
                         <span className="text-sm text-muted-foreground sm:shrink-0 sm:ml-4">
-                          {seg.paragraphs.length} paragraphs
                         </span>
                       </Link>
                     </li>

app/books/owk/page.tsx

@@ -60,7 +60,6 @@ export default async function OwkPage() {
                           </p>
                         </div>
                         <span className="text-sm text-muted-foreground sm:shrink-0 sm:ml-4">
-                          {seg.paragraphs.length} paragraphs
                         </span>
                       </Link>
                     </li>

app/books/poy/page.tsx

@@ -60,7 +60,6 @@ export default async function PoyPage() {
                           </p>
                         </div>
                         <span className="text-sm text-muted-foreground sm:shrink-0 sm:ml-4">
-                          {seg.paragraphs.length} paragraphs
                         </span>
                       </Link>
                     </li>

app/books/pqpa/[chapter]/page.tsx

@@ -239,14 +239,7 @@ function SidebarLink({
   item: PqpaSidebarItem;
   isActive: boolean;
 }) {
-  let label: string;
-  if (item.type === "chapter" && item.chapter != null) {
-    // Extract just the title portion after "Chapter N: "
-    const titlePart = item.label.replace(/^Chapter \d+:\s*/, "");
-    label = `${item.chapter}. ${titlePart}`;
-  } else {
-    label = item.label;
-  }
+  const label = item.label;
 
   return (
     <Link

app/books/pqpa/page.tsx

@@ -64,7 +64,6 @@ export default async function PqpaPage() {
                           </p>
                         </div>
                         <span className="text-sm text-muted-foreground sm:shrink-0 sm:ml-4">
-                          {seg.paragraphs.length} paragraphs
                         </span>
                       </Link>
                     </li>
@@ -151,7 +150,6 @@ export default async function PqpaPage() {
                           </p>
                         </div>
                         <span className="text-sm text-muted-foreground sm:shrink-0 sm:ml-4">
-                          {seg.paragraphs.length} paragraphs
                         </span>
                       </Link>
                     </li>

app/books/rv/page.tsx

@@ -60,7 +60,6 @@ export default async function RvPage() {
                           </p>
                         </div>
                         <span className="text-sm text-muted-foreground sm:shrink-0 sm:ml-4">
-                          {seg.paragraphs.length} paragraphs
                         </span>
                       </Link>
                     </li>

app/books/ssr/page.tsx

@@ -64,7 +64,6 @@ export default async function SsrPage() {
                           </p>
                         </div>
                         <span className="text-sm text-muted-foreground sm:shrink-0 sm:ml-4">
-                          {seg.paragraphs.length} paragraphs
                         </span>
                       </Link>
                     </li>
@@ -123,7 +122,6 @@ export default async function SsrPage() {
                           </p>
                         </div>
                         <span className="text-sm text-muted-foreground sm:shrink-0 sm:ml-4">
-                          {seg.paragraphs.length} paragraphs
                         </span>
                       </Link>
                     </li>

app/books/sva/page.tsx

@@ -64,7 +64,6 @@ export default async function SvaPage() {
                           </p>
                         </div>
                         <span className="text-sm text-muted-foreground sm:shrink-0 sm:ml-4">
-                          {seg.paragraphs.length} paragraphs
                         </span>
                       </Link>
                     </li>
@@ -123,7 +122,6 @@ export default async function SvaPage() {
                           </p>
                         </div>
                         <span className="text-sm text-muted-foreground sm:shrink-0 sm:ml-4">
-                          {seg.paragraphs.length} paragraphs
                         </span>
                       </Link>
                     </li>

app/books/tlc/[chapter]/page.tsx

@@ -141,6 +141,31 @@ function TlcSidebar({
   const introItems = items.filter((item) => item.type === "intro-segment");
   const chapterItems = items.filter((item) => item.type === "chapter");
 
+  // Group chapters by part (if parts exist)
+  const hasParts = chapterItems.some((item) => item.partNumber != null);
+
+  const partGroups: {
+    partNumber: number;
+    partTitle: string;
+    chapters: TlcSidebarItem[];
+  }[] = [];
+  if (hasParts) {
+    const partMap = new Map<
+      number,
+      { partTitle: string; chapters: TlcSidebarItem[] }
+    >();
+    for (const item of chapterItems) {
+      const pn = item.partNumber ?? 0;
+      const pt = item.partTitle ?? `Part ${pn}`;
+      if (!partMap.has(pn)) partMap.set(pn, { partTitle: pt, chapters: [] });
+      partMap.get(pn)!.chapters.push(item);
+    }
+    for (const [partNumber, { partTitle, chapters }] of partMap) {
+      partGroups.push({ partNumber, partTitle, chapters });
+    }
+    partGroups.sort((a, b) => a.partNumber - b.partNumber);
+  }
+
   return (
     <aside className="hidden lg:block w-56 shrink-0 sticky top-[89px] self-start max-h-[calc(100vh-89px)] overflow-y-auto py-8 pr-4">
       {/* Front Matter */}
@@ -161,23 +186,40 @@ function TlcSidebar({
         </>
       )}
 
-      {/* Chapters */}
-      {chapterItems.length > 0 && (
-        <>
-          <h2 className="text-xs font-bold uppercase tracking-wider text-muted-foreground mb-3 px-2">
-            Chapters
-          </h2>
-          <nav className="flex flex-col gap-0.5">
-            {chapterItems.map((item) => (
-              <SidebarLink
-                key={item.slug}
-                item={item}
-                isActive={item.slug === currentSlug}
-              />
-            ))}
-          </nav>
-        </>
-      )}
+      {/* Chapters — grouped by part if available */}
+      {hasParts
+        ? partGroups.map((group) => (
+            <div key={group.partNumber} className="mb-4">
+              <h2 className="text-xs font-bold uppercase tracking-wider text-muted-foreground mb-3 px-2">
+                {group.partTitle}
+              </h2>
+              <nav className="flex flex-col gap-0.5">
+                {group.chapters.map((item) => (
+                  <SidebarLink
+                    key={item.slug}
+                    item={item}
+                    isActive={item.slug === currentSlug}
+                  />
+                ))}
+              </nav>
+            </div>
+          ))
+        : chapterItems.length > 0 && (
+            <>
+              <h2 className="text-xs font-bold uppercase tracking-wider text-muted-foreground mb-3 px-2">
+                Chapters
+              </h2>
+              <nav className="flex flex-col gap-0.5">
+                {chapterItems.map((item) => (
+                  <SidebarLink
+                    key={item.slug}
+                    item={item}
+                    isActive={item.slug === currentSlug}
+                  />
+                ))}
+              </nav>
+            </>
+          )}
     </aside>
   );
 }
@@ -189,14 +231,7 @@ function SidebarLink({
   item: TlcSidebarItem;
   isActive: boolean;
 }) {
-  let label: string;
-  if (item.type === "chapter" && item.chapter != null) {
-    // Extract just the title portion after "Chapter N: "
-    const titlePart = item.label.replace(/^Chapter \d+:\s*/, "");
-    label = `${item.chapter}. ${titlePart}`;
-  } else {
-    label = item.label;
-  }
+  const label = item.label;
 
   return (
     <Link

app/books/tlc/page.tsx

@@ -68,7 +68,6 @@ export default async function TlcPage() {
                           </p>
                         </div>
                         <span className="text-sm text-muted-foreground sm:shrink-0 sm:ml-4">
-                          {seg.paragraphs.length} paragraphs
                         </span>
                       </Link>
                     </li>

app/books/tlk/[chapter]/page.tsx

@@ -226,14 +226,7 @@ function SidebarLink({
   item: TlkSidebarItem;
   isActive: boolean;
 }) {
-  let label: string;
-  if (item.type === "chapter" && item.chapter != null) {
-    // Extract just the title portion after "Chapter N: "
-    const titlePart = item.label.replace(/^Chapter \d+:\s*/, "");
-    label = `${item.chapter}. ${titlePart}`;
-  } else {
-    label = item.label;
-  }
+  const label = item.label;
 
   return (
     <Link

app/books/tlk/page.tsx

@@ -64,7 +64,6 @@ export default async function TlkPage() {
                           </p>
                         </div>
                         <span className="text-sm text-muted-foreground sm:shrink-0 sm:ml-4">
-                          {seg.paragraphs.length} paragraphs
                         </span>
                       </Link>
                     </li>
@@ -126,7 +125,6 @@ export default async function TlkPage() {
                           </p>
                         </div>
                         <span className="text-sm text-muted-foreground sm:shrink-0 sm:ml-4">
-                          {seg.paragraphs.length} paragraphs
                         </span>
                       </Link>
                     </li>

app/books/tqk/[chapter]/page.tsx

@@ -226,14 +226,7 @@ function SidebarLink({
   item: TqkSidebarItem;
   isActive: boolean;
 }) {
-  let label: string;
-  if (item.type === "chapter" && item.chapter != null) {
-    // Extract just the title portion after "Chapter N: "
-    const titlePart = item.label.replace(/^Chapter \d+:\s*/, "");
-    label = `${item.chapter}. ${titlePart}`;
-  } else {
-    label = item.label;
-  }
+  const label = item.label;
 
   return (
     <Link

app/books/tqk/page.tsx

@@ -64,7 +64,6 @@ export default async function TqkPage() {
                           </p>
                         </div>
                         <span className="text-sm text-muted-foreground sm:shrink-0 sm:ml-4">
-                          {seg.paragraphs.length} paragraphs
                         </span>
                       </Link>
                     </li>
@@ -126,7 +125,6 @@ export default async function TqkPage() {
                           </p>
                         </div>
                         <span className="text-sm text-muted-foreground sm:shrink-0 sm:ml-4">
-                          {seg.paragraphs.length} paragraphs
                         </span>
                       </Link>
                     </li>