feat: image compress before upload

components/selection-toolbar/compose-post.tsx

@@ -27,6 +27,7 @@ import {
 import { posts, SocialError } from "@/lib/social";
 import { buildHighlightUrl } from "@/lib/text-highlight";
 import { getSourceReference } from "@/lib/source-reference";
+import { compressImage } from "@/lib/compress-image";
 import { useSharePost } from "@/components/social/share-post-provider";
 
 const MAX_IMAGES = 5;
@@ -75,7 +76,12 @@ export function ComposePost({
     await Promise.all(
       picked.map(async (file, i) => {
         try {
-          const url = await posts.uploadImage(file);
+          // Compress in the browser before the presigned PUT — keeps
+          // R2 storage bounded, makes share pre-fetch fast, strips
+          // EXIF as a side effect. Falls back to the original file
+          // on any decode failure.
+          const compressed = await compressImage(file);
+          const url = await posts.uploadImage(compressed);
           setImages((prev) => {
             const next = [...prev];
             next[baseIndex + i] = { url, uploading: false };