feat: personal room name overrides (MSC4431-style)

Users can right-click any room and 'Rename for me...' to set a local
display name visible only to them. Stored in account data under
io.lotus.room_names. Shows a pencil indicator on renamed rooms.
useLocalRoomName() hook overrides useRoomName() when a local name exists.

Also includes:
- Rich room topic rendering via RoomTopicContent object (formatted_body
  support in RoomTopicViewer with HTML sanitization via sanitizeCustomHtml)
- Edit history viewer: clicking '(edited)' on a message opens a modal
  showing all prior versions with timestamps (EditHistoryModal.tsx)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/app/components/message/content/FallbackContent.tsx

@@ -66,8 +66,25 @@ export const MessageVerificationRequestContent = as<'div', { children?: never }>
   ),
 );
 
-export const MessageEditedContent = as<'span', { children?: never }>(({ ...props }, ref) => (
-  <Text as="span" size="T200" priority="300" {...props} ref={ref}>
-    {' (edited)'}
-  </Text>
-));
+export const MessageEditedContent = as<
+  'span',
+  { children?: never; onEditHistoryClick?: () => void }
+>(({ onEditHistoryClick, ...props }, ref) =>
+  onEditHistoryClick ? (
+    <span ref={ref} {...(props as React.HTMLAttributes<HTMLSpanElement>)}>
+      <button
+        type="button"
+        onClick={onEditHistoryClick}
+        style={{ cursor: 'pointer', background: 'none', border: 'none', padding: 0 }}
+      >
+        <Text as="span" size="T200" priority="300">
+          {' (edited)'}
+        </Text>
+      </button>
+    </span>
+  ) : (
+    <Text as="span" size="T200" priority="300" {...props} ref={ref}>
+      {' (edited)'}
+    </Text>
+  ),
+);