fix: chat accepts posts

components/chat/message-attachments.tsx

@@ -18,6 +18,7 @@ import { LinkPreviewCard } from "@/components/chat/link-preview-card";
 import { MediaGrid } from "@/components/chat/media-grid";
 import { MediaLightbox } from "@/components/chat/media-lightbox";
 import { QuoteCard } from "@/components/chat/quote-card";
+import { SharedPostCard } from "@/components/chat/shared-post-card";
 import { attachmentUrl, type Attachment } from "@/lib/chat";
 
 function humanSize(bytes?: number | null): string {
@@ -58,6 +59,9 @@ export function MessageAttachments({
 
         {rest.map((a) => {
           switch (a.kind) {
+            case "entity":
+              return <SharedPostCard key={a.id} attachment={a} />;
+
             case "quote":
               return <QuoteCard key={a.id} attachment={a} />;
 

components/chat/share-to-chat-dialog.tsx

@@ -37,12 +37,16 @@ type SendState = "idle" | "sending" | "sent";
 export function ShareToChatDialog({
   body = "",
   quote,
+  entity,
   onClose,
 }: {
   /** Plain message text. Empty when sending a quote on its own. */
   body?: string;
   /** A passage from the library, sent as a tappable quotation. */
   quote?: QuotePayload;
+  /** A post, sent as a card. Only the reference travels — the BFF resolves
+   *  the contents and re-checks visibility for each viewer. */
+  entity?: { type: "post"; id: string };
   onClose: () => void;
 }) {
   const { user } = useAuth();
@@ -111,7 +115,7 @@ export function ShareToChatDialog({
     mark(handle, "sending");
     try {
       const id = conversationId ?? (await chat.openDM(handle)).id;
-      await chat.send(id, body, { quote });
+      await chat.send(id, body, { quote, entity });
       mark(handle, "sent");
     } catch {
       mark(handle, "idle");

components/chat/shared-post-card.tsx

@@ -0,0 +1,75 @@
+"use client";
+
+/**
+ * A post shared into a chat, rendered as a card with its author.
+ *
+ * The contents are resolved by the BFF on every read, per viewer — never from
+ * a snapshot frozen at send time. So a post that has since been deleted or
+ * hidden arrives as `entity_unavailable` and renders as a tombstone rather
+ * than quietly showing content the reader is no longer allowed to see.
+ */
+
+import Link from "next/link";
+import { ImageOff } from "lucide-react";
+import { UserAvatar } from "@/components/ui/user-avatar";
+import type { Attachment } from "@/lib/chat";
+
+export function SharedPostCard({ attachment }: { attachment: Attachment }) {
+  const post = attachment.entity;
+
+  if (!post || attachment.entity_unavailable) {
+    return (
+      <div className="mt-1 flex items-center gap-2 rounded-lg border border-border bg-muted/30 px-3 py-2.5">
+        <ImageOff className="size-4 shrink-0 text-muted-foreground" aria-hidden />
+        <span className="text-sm text-muted-foreground">
+          This post is no longer available
+        </span>
+      </div>
+    );
+  }
+
+  return (
+    <Link
+      href={`/u/${encodeURIComponent(post.author_handle)}/posts#post-${post.id}`}
+      className="mt-1 block overflow-hidden rounded-lg border border-border bg-card transition-colors hover:bg-muted/40"
+    >
+      <span className="flex items-center gap-2 px-3 py-2">
+        <UserAvatar
+          src={post.author_avatar_url ?? null}
+          name={post.author_name}
+          className="size-6 shrink-0"
+        />
+        <span className="min-w-0 flex-1">
+          <span className="block truncate text-xs font-medium text-foreground">
+            {post.author_name}
+          </span>
+          <span className="block truncate text-[11px] text-muted-foreground">
+            @{post.author_handle}
+          </span>
+        </span>
+      </span>
+
+      {post.image_url && (
+        // eslint-disable-next-line @next/next/no-img-element
+        <img
+          src={post.image_url}
+          alt=""
+          loading="lazy"
+          className="aspect-square w-full object-cover"
+        />
+      )}
+
+      {post.caption && (
+        <span className="block px-3 py-2 text-sm leading-relaxed text-foreground line-clamp-3">
+          {post.caption}
+        </span>
+      )}
+
+      {post.source_title && (
+        <span className="block truncate px-3 pb-2 text-xs text-muted-foreground">
+          {post.source_title}
+        </span>
+      )}
+    </Link>
+  );
+}