saved sessions: replace transient history with persistent DB storage and auto-save

- Add saved_sessions table and CRUD endpoints (save, list, resume, update, delete)
- Save is instant (no LLM summarization), stores exact conversation with tool calls
- Resume loads full message history into chat UI, sends transcript to agent on first message
- Auto-save updates DB after every agent response once a session is saved
- Delete old filesystem-based session/group management (sessions router, useChatSessions, useChatGroups)
- Clean up ChatHeader, SessionList, ChatDetailPanel for saved sessions flow

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

src/servers/api/saved-sessions/saved-sessions.ts

@@ -0,0 +1,160 @@
+import { createRouter } from '../../create-router';
+import {
+  listSavedSessions,
+  getSavedSession,
+  createSavedSession,
+  updateSavedSessionMessages,
+  deleteSavedSession,
+} from 'officerdb';
+import * as storage from '../pi/storage';
+import { getHomeDirForRole } from '../../data-path';
+import type { Message, MessageCost } from '../pi/types';
+
+export const savedSessionsRouter = createRouter();
+
+// POST /saved-sessions — save session instantly (no LLM summary)
+savedSessionsRouter.post('/', async (ctx) => {
+  const user = ctx.get('user');
+  const { sessionId } = ctx.get('body') as { sessionId: string };
+
+  if (!sessionId) {
+    return ctx.json({ error: 'sessionId is required' }, 400);
+  }
+
+  const homeDir = getHomeDirForRole(user.email, user.role);
+
+  let meta;
+  let messages: Message[];
+  try {
+    const loaded = await storage.loadSession(homeDir, sessionId);
+    meta = loaded.meta;
+    messages = loaded.messages;
+  } catch {
+    return ctx.json({ error: 'Session not found on disk' }, 404);
+  }
+
+  try {
+    const saved = await createSavedSession({
+      userId: user.id,
+      provider: meta.model,
+      context: meta.context ?? null,
+      contextId: meta.contextId ?? null,
+      title: meta.title,
+      summary: meta.title,
+      rawMessages: messages,
+      cwd: meta.cwd,
+      cost: meta.cost as unknown as Record<string, unknown>,
+    });
+
+    return ctx.json(saved, 201);
+  } catch (err) {
+    console.error('Failed to create saved session:', err);
+    return ctx.json({ error: 'Failed to save session' }, 500);
+  }
+});
+
+// GET /saved-sessions — list (no rawMessages)
+savedSessionsRouter.get('/', async (ctx) => {
+  const user = ctx.get('user');
+  const rows = await listSavedSessions(user.id);
+  return ctx.json(rows);
+});
+
+// GET /saved-sessions/:id — full record
+savedSessionsRouter.get('/:id', async (ctx) => {
+  const user = ctx.get('user');
+  const id = Number(ctx.req.param('id'));
+
+  if (Number.isNaN(id)) {
+    return ctx.json({ error: 'Invalid id' }, 400);
+  }
+
+  const session = await getSavedSession(id, user.id);
+  if (!session) {
+    return ctx.json({ error: 'Not found' }, 404);
+  }
+
+  return ctx.json(session);
+});
+
+// PUT /saved-sessions/:id — update messages from disk (auto-save after each turn)
+savedSessionsRouter.put('/:id', async (ctx) => {
+  const user = ctx.get('user');
+  const id = Number(ctx.req.param('id'));
+  const { sessionId } = ctx.get('body') as { sessionId: string };
+
+  if (Number.isNaN(id)) {
+    return ctx.json({ error: 'Invalid id' }, 400);
+  }
+
+  if (!sessionId) {
+    return ctx.json({ error: 'sessionId is required' }, 400);
+  }
+
+  const homeDir = getHomeDirForRole(user.email, user.role);
+
+  let meta;
+  let messages: Message[];
+  try {
+    const loaded = await storage.loadSession(homeDir, sessionId);
+    meta = loaded.meta;
+    messages = loaded.messages;
+  } catch {
+    return ctx.json({ error: 'Session not found on disk' }, 404);
+  }
+
+  const updated = await updateSavedSessionMessages(
+    id,
+    user.id,
+    messages,
+    meta.cost as unknown as Record<string, unknown>,
+  );
+
+  if (!updated) {
+    return ctx.json({ error: 'Not found' }, 404);
+  }
+
+  return ctx.json({ ok: true });
+});
+
+// DELETE /saved-sessions/:id
+savedSessionsRouter.delete('/:id', async (ctx) => {
+  const user = ctx.get('user');
+  const id = Number(ctx.req.param('id'));
+
+  if (Number.isNaN(id)) {
+    return ctx.json({ error: 'Invalid id' }, 400);
+  }
+
+  const deleted = await deleteSavedSession(id, user.id);
+  if (!deleted) {
+    return ctx.json({ error: 'Not found' }, 404);
+  }
+
+  return ctx.json({ ok: true });
+});
+
+// POST /saved-sessions/:id/resume — get full session for resuming
+savedSessionsRouter.post('/:id/resume', async (ctx) => {
+  const user = ctx.get('user');
+  const id = Number(ctx.req.param('id'));
+
+  if (Number.isNaN(id)) {
+    return ctx.json({ error: 'Invalid id' }, 400);
+  }
+
+  const session = await getSavedSession(id, user.id);
+  if (!session) {
+    return ctx.json({ error: 'Not found' }, 404);
+  }
+
+  const cost = session.cost as unknown as MessageCost;
+
+  return ctx.json({
+    context: session.context,
+    cwd: session.cwd,
+    model: session.provider,
+    cost,
+    rawMessages: session.rawMessages,
+  });
+});