chat: retire the old saved-session store (Stage 4a)

Deletes all session persistence that isn't Claude's native transcript store, per
the "only harness-native session management survives" rule.

Backend: delete api/pi/storage.ts (meta.json+messages.json file store), the
api/saved-sessions router (+ unmount), the /pi/sessions REST endpoints, and the
storage.save/loadSession calls in the chat WS handler (in-memory session-manager
stays for live turns; no disk persistence — Claude's transcript is the record).
Also drops the Postgres saved_sessions layer: schema/chat.ts, queries/saved-sessions.ts,
its types and re-exports.

Frontend: delete state/useSavedSessions, ChatList, and the ChatHistory Widget
(all pure saved-session UI); slim ChatHeader to a label; strip the auto-load-latest
+ Save wiring from ChatPanelWrapper and ChatDetailPanel; drop the old resume path
from useChat and SessionListPage; remove the /chat/saved/:id route and the
useInitialData prefetch.

Behavior removed (intended): the Save-session button, email/project panels
auto-resuming the last chat, and /chat/saved/:id. /chat itself is unchanged —
already fully on Claude transcripts. The orphaned saved_sessions Postgres table
is dropped on the next `bun db:push`.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/workspaces/state/src/index.ts

@@ -11,8 +11,6 @@ export { useRecentModels } from './useRecentModels';
 export { usePlans } from './usePlans';
 export { useLandingPage } from './useLandingPage';
 export { useServerSettings } from './useServerSettings';
-export { useSavedSessions } from './useSavedSessions';
-export type { UseSavedSessionsType, SavedSessionEntry } from './useSavedSessions';
 export { useUserApps } from './useUserApps';
 export type { AppManifest } from './useUserApps';
 export { useServerEnvironment } from './useServerEnvironment';

src/workspaces/state/src/useSavedSessions.ts

@@ -1,105 +0,0 @@
-import { useAuth } from 'hooks/useAuth';
-import { useClient } from 'hooks/useClient';
-import { useQuery, useQueryClient } from '@tanstack/react-query';
-import { toast } from 'sonner';
-
-export type SavedSessionEntry = {
-  id: number;
-  provider: string;
-  context: string | null;
-  contextId: string | null;
-  title: string;
-  summary: string;
-  cwd: string;
-  cost: { inputTokens: number; outputTokens: number; totalUSD: number };
-  createdAt: string;
-};
-
-type RawMessage = {
-  id: string;
-  timestamp: number;
-  role: 'user' | 'assistant' | 'tool';
-  text?: string;
-  model?: string;
-  cost?: { inputTokens: number; outputTokens: number; totalUSD: number };
-  toolCallId?: string;
-  toolName?: string;
-  toolInput?: Record<string, unknown>;
-  output?: string;
-  isError?: boolean;
-};
-
-export type ResumeResult = {
-  context: string | null;
-  cwd: string;
-  model: string;
-  cost: { inputTokens: number; outputTokens: number; totalUSD: number };
-  rawMessages: RawMessage[];
-};
-
-export type { RawMessage };
-
-export function messagesToTranscript(messages: RawMessage[]): string {
-  const lines: string[] = [];
-
-  for (const msg of messages) {
-    if (msg.role === 'user' && msg.text) {
-      lines.push(`User: ${msg.text}`);
-    } else if (msg.role === 'assistant' && msg.text) {
-      lines.push(`Assistant: ${msg.text}`);
-    } else if (msg.role === 'tool') {
-      const outcome = msg.isError ? `Error: ${msg.output}` : msg.output ? 'Success' : 'Pending';
-      lines.push(`Tool [${msg.toolName}]: ${outcome}`);
-    }
-  }
-
-  return lines.join('\n\n');
-}
-
-export function useSavedSessions() {
-  const client = useClient();
-  const queryClient = useQueryClient();
-  const { isAuthenticated } = useAuth();
-
-  const { data: sessions = [], isLoading } = useQuery<SavedSessionEntry[]>({
-    queryKey: ['SAVED_SESSIONS'],
-    enabled: isAuthenticated,
-    queryFn: () => client.get<SavedSessionEntry[]>('/saved-sessions'),
-  });
-
-  async function saveSession(sessionId: string) {
-    try {
-      const result = await client.post<SavedSessionEntry>('/saved-sessions', { sessionId });
-      queryClient.invalidateQueries({ queryKey: ['SAVED_SESSIONS'] });
-      toast.success('Session saved');
-      return result;
-    } catch (err) {
-      toast.error('Failed to save session');
-      throw err;
-    }
-  }
-
-  async function deleteSavedSession(id: number) {
-    await client.delete(`/saved-sessions/${id}`);
-    queryClient.setQueryData<SavedSessionEntry[]>(['SAVED_SESSIONS'], (prev) => prev?.filter((s) => s.id !== id) ?? []);
-  }
-
-  async function resumeSession(id: number) {
-    return client.post<ResumeResult>(`/saved-sessions/${id}/resume`);
-  }
-
-  async function updateSessionMessages(savedId: number, sessionId: string, resumedMessageCount?: number) {
-    await client.put(`/saved-sessions/${savedId}`, { sessionId, resumedMessageCount });
-  }
-
-  return {
-    sessions,
-    isLoading,
-    saveSession,
-    deleteSavedSession,
-    resumeSession,
-    updateSessionMessages,
-  };
-}
-
-export type UseSavedSessionsType = ReturnType<typeof useSavedSessions>;