batch4: chats-in-sessions, force-send, /compact, right-rail file browser

Session 1:N Chat data model with backfill. Workspace switches to client-side
multi-tab pane management. Right-rail file browser with float-over viewer and
click-drag line selection replaces FileBrowserPane. Adds /compact streaming
summarizer (respects compact markers in context builder), force-send (cancels
in-flight, persists partial as 'cancelled', awaits cancellation completion via
deferred Promise + 5s timeout), message queue, stop generation, chat
auto-rename, session archive/unarchive with Closed Sessions section on repo
landing page. CHECK constraints on sessions.status, messages.role,
messages.status with KEEP IN SYNC comments tying to MESSAGE_ROLES /
MESSAGE_STATUSES const arrays. Deletes dead pane routes/hook and the
api.panes.* client block.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

apps/server/src/schema.sql

@@ -21,11 +21,11 @@ CREATE INDEX IF NOT EXISTS idx_sessions_project ON sessions(project_id, updated_
 CREATE TABLE IF NOT EXISTS messages (
   id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
   session_id UUID NOT NULL REFERENCES sessions(id) ON DELETE CASCADE,
-  role TEXT NOT NULL CHECK (role IN ('user', 'assistant', 'tool')),
+  role TEXT NOT NULL,
   content TEXT NOT NULL DEFAULT '',
   tool_calls JSONB,
   tool_results JSONB,
-  status TEXT NOT NULL DEFAULT 'complete' CHECK (status IN ('streaming', 'complete', 'failed')),
+  status TEXT NOT NULL DEFAULT 'complete',
   last_seq INT NOT NULL DEFAULT 0,
   created_at TIMESTAMPTZ NOT NULL DEFAULT NOW()
 );
@@ -47,6 +47,8 @@ CREATE TABLE IF NOT EXISTS settings (
 
 INSERT INTO settings (key, value) VALUES ('default_model', '"qwen3.6-35b-a3b-mxfp4"') ON CONFLICT (key) DO NOTHING;
 
+-- DEPRECATED: client-side pane state as of v1.2-batch4. Table retained per
+-- additive schema rule; no writes. Drop in a future destructive migration.
 CREATE TABLE IF NOT EXISTS session_panes (
   id           UUID PRIMARY KEY DEFAULT gen_random_uuid(),
   session_id   UUID NOT NULL REFERENCES sessions(id) ON DELETE CASCADE,
@@ -66,3 +68,67 @@ FROM sessions s
 WHERE NOT EXISTS (
   SELECT 1 FROM session_panes p WHERE p.session_id = s.id
 );
+
+-- v1.2: sessions.status (open | archived)
+ALTER TABLE sessions ADD COLUMN IF NOT EXISTS status TEXT NOT NULL DEFAULT 'open';
+
+-- v1.2: chats table
+CREATE TABLE IF NOT EXISTS chats (
+  id           UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+  session_id   UUID NOT NULL REFERENCES sessions(id) ON DELETE CASCADE,
+  name         TEXT,
+  status       TEXT NOT NULL DEFAULT 'open' CHECK (status IN ('open', 'closed')),
+  created_at   TIMESTAMPTZ NOT NULL DEFAULT clock_timestamp(),
+  updated_at   TIMESTAMPTZ NOT NULL DEFAULT clock_timestamp()
+);
+CREATE INDEX IF NOT EXISTS idx_chats_session_status ON chats (session_id, status, updated_at DESC);
+
+-- v1.2: messages.chat_id + messages.kind
+ALTER TABLE messages ADD COLUMN IF NOT EXISTS chat_id UUID REFERENCES chats(id) ON DELETE CASCADE;
+ALTER TABLE messages ADD COLUMN IF NOT EXISTS kind TEXT NOT NULL DEFAULT 'message';
+CREATE INDEX IF NOT EXISTS idx_messages_chat ON messages (chat_id, created_at);
+
+-- Backfill: one chat per existing session that has none yet
+INSERT INTO chats (session_id, name, status, created_at, updated_at)
+SELECT s.id, s.name, 'open', s.created_at, s.updated_at
+FROM sessions s
+WHERE NOT EXISTS (
+  SELECT 1 FROM chats c WHERE c.session_id = s.id
+);
+
+-- Backfill: link orphaned messages to their session's first chat
+UPDATE messages SET chat_id = (
+  SELECT c.id FROM chats c WHERE c.session_id = messages.session_id ORDER BY c.created_at ASC LIMIT 1
+)
+WHERE chat_id IS NULL;
+
+-- Enforce NOT NULL on chat_id once all rows are backfilled
+DO $$
+BEGIN
+  IF EXISTS (
+    SELECT 1 FROM information_schema.columns
+    WHERE table_name = 'messages' AND column_name = 'chat_id' AND is_nullable = 'YES'
+  ) AND NOT EXISTS (
+    SELECT 1 FROM messages WHERE chat_id IS NULL
+  ) THEN
+    ALTER TABLE messages ALTER COLUMN chat_id SET NOT NULL;
+  END IF;
+END $$;
+
+-- v1.2.1: CHECK constraints for sessions.status and messages (role, status)
+-- KEEP IN SYNC: apps/server/src/types/api.ts (MESSAGE_ROLES, MESSAGE_STATUSES, SessionStatus)
+DO $$
+BEGIN
+  IF NOT EXISTS (SELECT 1 FROM pg_constraint WHERE conname = 'sessions_status_chk') THEN
+    ALTER TABLE sessions ADD CONSTRAINT sessions_status_chk
+      CHECK (status IN ('open', 'archived'));
+  END IF;
+  IF NOT EXISTS (SELECT 1 FROM pg_constraint WHERE conname = 'messages_role_chk') THEN
+    ALTER TABLE messages ADD CONSTRAINT messages_role_chk
+      CHECK (role IN ('user', 'assistant', 'system', 'tool'));
+  END IF;
+  IF NOT EXISTS (SELECT 1 FROM pg_constraint WHERE conname = 'messages_status_chk') THEN
+    ALTER TABLE messages ADD CONSTRAINT messages_status_chk
+      CHECK (status IN ('streaming', 'complete', 'failed', 'cancelled'));
+  END IF;
+END $$;