persist panel sizes for email and automation screens, fix session title from prompt prefix

- switch email and automation screens from WorkspaceLayout to WorkspaceView + useWorkspacesState
- add promptPrefix prop to WorkspaceView, thread into WorkspaceContext
- automation dynamically adds/removes chat panel while preserving persisted sizes
- use displayText for session title so prompt prefix doesn't leak into titles
- fix email context filter to match screens/email workspace key

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

src/servers/api/pi/websocket.ts

@@ -242,7 +242,7 @@ function createEventHandler(sessionId: string, model: string, cwd: string, stora
 
 async function handleChat(
   ws: ServerWebSocket<WSData>,
-  msg: { prompt: string; sessionId?: string; model?: string; cwd?: string; cwdRoot?: string; sandboxed?: boolean; groupSlug?: string; attachmentIds?: string[]; thinking?: string; context?: string; contextId?: string }
+  msg: { prompt: string; displayText?: string; sessionId?: string; model?: string; cwd?: string; cwdRoot?: string; sandboxed?: boolean; groupSlug?: string; attachmentIds?: string[]; thinking?: string; context?: string; contextId?: string }
 ): Promise<void> {
   const { email, username, userId } = ws.data;
   const sessionId = msg.sessionId || randomUUID();
@@ -336,7 +336,7 @@ async function handleChat(
   session.meta.updatedAt = Date.now();
 
   if (!session.meta.title) {
-    session.meta.title = msg.prompt.slice(0, 100);
+    session.meta.title = (msg.displayText ?? msg.prompt).slice(0, 100);
   }
 
   // Set thinking level if provided