feat: content enhancements — URL shortening, hashtag collapse, bot badge, edit indicator (Release 7)

Shorten long URLs in post content (30 char display limit with tooltip).
Collapse hashtag-heavy paragraphs into expandable <details> toggle.
Show BOT badge for Service/Application actors. Show pencil icon for
edited posts with hover tooltip showing edit timestamp.

Confab-Link: http://localhost:8080/sessions/e9d666ac-3c90-4298-9e92-9ac9d142bc06

lib/item-processing.js

@@ -8,6 +8,7 @@
 
 import { stripQuoteReferenceHtml } from "./og-unfurl.js";
 import { replaceCustomEmoji } from "./emoji-utils.js";
+import { shortenDisplayUrls, collapseHashtagStuffing } from "./content-utils.js";
 
 /**
  * Post-process timeline items for rendering.
@@ -31,7 +32,10 @@ export async function postProcessItems(items, options = {}) {
   // 3. Replace custom emoji shortcodes with <img> tags
   applyCustomEmoji(items);
 
-  // 4. Build interaction map (likes/boosts) — empty when no collection
+  // 4. Shorten long URLs and collapse hashtag stuffing in content
+  applyContentEnhancements(items);
+
+  // 5. Build interaction map (likes/boosts) — empty when no collection
   const interactionMap = options.interactionsCol
     ? await buildInteractionMap(items, options.interactionsCol)
     : {};
@@ -154,6 +158,24 @@ function applyCustomEmoji(items) {
   }
 }
 
+/**
+ * Shorten long URLs and collapse hashtag-heavy paragraphs in content.
+ * Mutates items in place.
+ *
+ * @param {Array} items
+ */
+function applyContentEnhancements(items) {
+  for (const item of items) {
+    if (item.content?.html) {
+      item.content.html = shortenDisplayUrls(item.content.html);
+      item.content.html = collapseHashtagStuffing(item.content.html);
+    }
+    if (item.quote?.content?.html) {
+      item.quote.content.html = shortenDisplayUrls(item.quote.content.html);
+    }
+  }
+}
+
 /**
  * Build interaction map (likes/boosts) for template rendering.
  * Returns { [uid]: { like: true, boost: true } }.