feat(mvp): Phase 1 control layer + API vertical slice

Implements the Phase 1 MVP from the README: a stateless control layer + HTTP
API over a centralized database, with hook-enforced test/push gates.

- DB layer: SQLAlchemy Core, one schema rendering both Postgres (BIGSERIAL /
  TIMESTAMPTZ / JSONB) and SQLite (INTEGER PK / TEXT / JSON) via portable types;
  native ON CONFLICT DO UPDATE checkmark upsert on both dialects.
- Alembic dual-dialect migrations (render_as_batch for SQLite); tests run a real
  `alembic upgrade head`.
- FastAPI: projects/agents/checkmark/log/answer/resume + shared log/context
  routes, single global bearer token, higher-trust token gating shared-context
  writes, project isolation on every route.
- Hooks (`python -m handler.hooks <event>`): Stop test gate (block on red),
  PreToolUse AskUserQuestion defer + `git push` gate (tests then throwaway
  build), Notification generic webhook (no-op without WEBHOOK_URL). Identity via
  env injected at spawn; verify is the mock seam.
- Control CLI: spawn/list/attach/kill, hard `.mise.toml [tasks.test]` gate,
  generated per-agent settings.json, identity + DATABASE_URL injected via tmux;
  tmux is the mock seam.
- 45 tests (SQLite), ruff clean. Live claude/tmux/mise spawning deferred behind
  the mocked seams.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01W5ZuS5pV1NS6eKsRZHXonY

tests/test_hook_gate.py

@@ -0,0 +1,79 @@
+"""PreToolUse: AskUserQuestion defer + git-push gate."""
+
+from __future__ import annotations
+
+from handler.db import repository as repo
+from handler.hooks import gate, verify
+from handler.hooks.context import HookInput, Identity
+
+
+def _seed(conn):
+    repo.create_project(conn, "p", "/tmp/p")
+    a = repo.create_agent(conn, "p", "a", "/tmp/p/a")
+    return Identity(a["id"], "p", "a", "/tmp/p/a")
+
+
+def _decision(result):
+    return result["hookSpecificOutput"]["permissionDecision"]
+
+
+def test_ask_user_question_is_deferred(conn):
+    ident = _seed(conn)
+    hi = HookInput(
+        {
+            "tool_name": "AskUserQuestion",
+            "tool_input": {"questions": [{"question": "Which DB?"}]},
+            "session_id": "s1",
+        },
+        "pre_tool_use",
+    )
+    result = gate.handle_ask_user_question(conn, ident, hi)
+    assert _decision(result) == "deny"
+
+    cm = repo.get_checkmark(conn, ident.agent_id)
+    assert cm["status"] == "paused_for_input"
+    assert cm["open_question"] == "Which DB?"
+    assert repo.get_latest_open_question(conn, ident.agent_id)["question"] == "Which DB?"
+
+
+def test_git_push_denied_when_tests_fail(conn, monkeypatch):
+    ident = _seed(conn)
+    monkeypatch.setattr(verify, "run_test", lambda cwd: (False, "1 failed"))
+    # Build must not even run when tests fail (cheap check first).
+    monkeypatch.setattr(
+        verify, "run_build", lambda cwd: (_ for _ in ()).throw(AssertionError("built"))
+    )
+    hi = HookInput(
+        {"tool_name": "Bash", "tool_input": {"command": "git push origin main"}},
+        "pre_tool_use",
+    )
+    result = gate.handle_git_push(conn, ident, hi)
+    assert _decision(result) == "deny"
+    assert repo.get_checkmark(conn, ident.agent_id)["tests_status"] == "fail"
+
+
+def test_git_push_denied_when_build_fails(conn, monkeypatch):
+    ident = _seed(conn)
+    monkeypatch.setattr(verify, "run_test", lambda cwd: (True, "ok"))
+    monkeypatch.setattr(verify, "run_build", lambda cwd: (False, "COPY failed"))
+    hi = HookInput({"tool_name": "Bash", "tool_input": {"command": "git push"}}, "pre_tool_use")
+    result = gate.handle_git_push(conn, ident, hi)
+    assert _decision(result) == "deny"
+    cm = repo.get_checkmark(conn, ident.agent_id)
+    assert cm["tests_status"] == "pass"
+    assert cm["build_status"] == "fail"
+
+
+def test_git_push_allowed_when_both_pass(conn, monkeypatch):
+    ident = _seed(conn)
+    monkeypatch.setattr(verify, "run_test", lambda cwd: (True, "ok"))
+    monkeypatch.setattr(verify, "run_build", lambda cwd: (True, "built"))
+    hi = HookInput({"tool_name": "Bash", "tool_input": {"command": "git push"}}, "pre_tool_use")
+    result = gate.handle_git_push(conn, ident, hi)
+    assert _decision(result) == "allow"
+
+
+def test_non_push_bash_is_ignored(conn):
+    ident = _seed(conn)
+    hi = HookInput({"tool_name": "Bash", "tool_input": {"command": "ls -la"}}, "pre_tool_use")
+    assert gate.handle(conn, ident, hi) == {}