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/RenderMessageContent.tsx

@@ -38,6 +38,7 @@ type RenderMessageContentProps = {
   msgType: string;
   ts: number;
   edited?: boolean;
+  onEditHistoryClick?: () => void;
   getContent: <T>() => T;
   mediaAutoLoad?: boolean;
   urlPreview?: boolean;
@@ -51,6 +52,7 @@ export function RenderMessageContent({
   msgType,
   ts,
   edited,
+  onEditHistoryClick,
   getContent,
   mediaAutoLoad,
   urlPreview,
@@ -77,6 +79,7 @@ export function RenderMessageContent({
         <MText
           style={{ marginTop: config.space.S200 }}
           edited={edited}
+          onEditHistoryClick={onEditHistoryClick}
           content={content}
           renderBody={(props) => (
             <RenderBody
@@ -133,6 +136,7 @@ export function RenderMessageContent({
     return (
       <MText
         edited={edited}
+        onEditHistoryClick={onEditHistoryClick}
         content={getContent()}
         renderBody={(props) => (
           <RenderBody
@@ -152,6 +156,7 @@ export function RenderMessageContent({
       <MEmote
         displayName={displayName}
         edited={edited}
+        onEditHistoryClick={onEditHistoryClick}
         content={getContent()}
         renderBody={(props) => (
           <RenderBody
@@ -170,6 +175,7 @@ export function RenderMessageContent({
     return (
       <MNotice
         edited={edited}
+        onEditHistoryClick={onEditHistoryClick}
         content={getContent()}
         renderBody={(props) => (
           <RenderBody