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/apps/officer-web/Screens/Dashboard/ChatHistory/index.tsx

@@ -1,16 +1,12 @@
-import { useEffect, useMemo, useRef } from 'react';
+import { useEffect, useMemo } from 'react';
 import { useParams, useNavigate } from 'react-router';
 import type { LayoutNode, SelectedSession } from 'officerdev';
-import type { ChatMessage } from 'officerdev';
 import { WorkspaceView } from 'officerdev';
 import { useIsMobile } from 'hooks/useIsMobile';
 import { useDashboardState } from 'state/useDashboardState';
 import { usePanelChannel } from 'hooks/usePanelChannel';
-import { useSavedSessions, messagesToTranscript, type RawMessage } from 'state/useSavedSessions';
 import { defaultLayout } from './defaultLayout';
 
-export { ChatHistory as ChatHistoryApp } from './Widget';
-
 // Allowed panel app types for the /chat screen
 const ALLOWED_APP_TYPES = new Set<string | null>(['chat-session-list', 'chat-detail', null]);
 
@@ -35,15 +31,12 @@ type SessionListPageProps = {
 };
 
 export const SessionListPage = ({ isNew }: SessionListPageProps) => {
-  const { sessionId, id: savedIdParam } = useParams<{ sessionId: string; id: string }>();
+  const { sessionId } = useParams<{ sessionId: string }>();
   const [, setSelected] = usePanelChannel<SelectedSession>('chat:selected-session', null);
   const rawWorkspace = useDashboardState<LayoutNode>('screens/chat', defaultLayout);
   const isMobile = useIsMobile();
   const navigate = useNavigate();
-  const { resumeSession } = useSavedSessions();
-  const loadedSavedIdRef = useRef<number | null>(null);
-  const savedId = savedIdParam ? Number(savedIdParam) : null;
-  const mobilePanelId = isMobile && (sessionId || isNew || savedId) ? 'chat-detail' : undefined;
+  const mobilePanelId = isMobile && (sessionId || isNew) ? 'chat-detail' : undefined;
 
   // Normalize synchronously so the wrong panel never renders
   const workspace = useMemo(() => {
@@ -64,38 +57,9 @@ export const SessionListPage = ({ isNew }: SessionListPageProps) => {
       setSelected({ id: `new:${Date.now()}` });
       return;
     }
-    if (savedId && !Number.isNaN(savedId) && loadedSavedIdRef.current !== savedId) {
-      loadedSavedIdRef.current = savedId;
-      resumeSession(savedId).then((result) => {
-        const rawMessages = result.rawMessages ?? [];
-        const chatMessages: ChatMessage[] = rawMessages.map((m: RawMessage) => {
-          if (m.role === 'user') return { role: 'user' as const, text: m.text || '' };
-          if (m.role === 'assistant') return { role: 'assistant' as const, id: m.id, text: m.text || '' };
-          if (m.role === 'tool') {
-            return {
-              role: 'tool' as const,
-              toolName: m.toolName || '',
-              toolInput: m.toolInput || {},
-              toolCallId: m.toolCallId || '',
-              output: m.output,
-              isError: m.isError,
-            };
-          }
-          return { role: 'assistant' as const, text: '' };
-        });
-        const transcript = messagesToTranscript(rawMessages);
-        setSelected({
-          id: `saved:${savedId}`,
-          model: result.model,
-          resumeSummary: transcript,
-          initialMessages: chatMessages,
-        });
-      });
-      return;
-    }
     if (!sessionId) return;
     setSelected({ id: sessionId });
-  }, [sessionId, isNew, savedId]);
+  }, [sessionId, isNew]);
 
   return (
     <div className="h-full w-full pt-2">