feat: bundle agent executables + web-driven claude login

Two changes so an operator can stand up and authenticate Handler entirely
from the browser, with a self-contained control image.

Bundle executables in the control image (Dockerfile.control)
- Node.js (NodeSource) + the Claude Code CLI, mise (official apt repo), and
  forge (git-pkgs/forge, built in a Go stage) join the existing git/tmux/ssh.
  No more bring-your-own binaries: live agent spawning, the verification gate,
  CI resolution, and the login flow all work out of the box. Installed under
  /usr so the /var/lib/handler VOLUME never masks them; mise apt source pinned
  to $TARGETARCH for the multi-arch (amd64/arm64) build.

Claude login from the web UI
- New login_start / login_submit command types (migration 0005) drive the
  interactive `claude /login` through the same enqueue→worker handoff every
  other control action uses — the API container has no claude binary.
- control/login.py opens `claude` in a dedicated tmux session, sends /login,
  selects the subscription account, and scrapes the claude.com authorization
  URL (tmux.capture_pane, -pJ so a wrapped URL rejoins); a second command feeds
  back the pasted code. Fully mockable via the tmux seam.
- API: POST /login/start, POST /login/submit (admin-gated).
- Dashboard: a "Claude Login" pane — a button that starts the flow, embeds the
  URL in an iframe (with a new-tab fallback, since claude.com may refuse
  framing), and takes the code to finish.

Also un-ignores frontend/lib/ (a broad Python `lib/` rule was swallowing the
UI's own api client + formatters, breaking rebuilds from a fresh clone) and
reconstructs those two source files; rebuilt static export committed.

Tests: control/login unit tests (tmux faked), worker dispatch, and API route
tests. Full suite green (195 tests), ruff clean.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01YKVyBmKvWDVgrFC9WER2f2

tests/test_api_login.py

@@ -0,0 +1,49 @@
+"""The web-login API surface: enqueue login_start / login_submit, admin-gated."""
+
+from __future__ import annotations
+
+
+def _admin(env):
+    # ADMIN_TOKEN is unset in the test env, so the admin gate falls back to AUTH_TOKEN.
+    return {"Authorization": f"Bearer {env['token']}"}
+
+
+def test_login_start_enqueues_command(client, env):
+    r = client.post("/login/start", headers=_admin(env))
+    assert r.status_code == 202
+    body = r.json()
+    assert body["type"] == "login_start"
+    assert body["status"] == "queued"
+    assert body["requested_by"] == "operator:web"
+
+
+def test_login_submit_enqueues_command_with_code(client, env):
+    r = client.post("/login/submit", headers=_admin(env), json={"code": "auth-xyz"})
+    assert r.status_code == 202
+    body = r.json()
+    assert body["type"] == "login_submit"
+    assert body["payload"] == {"code": "auth-xyz"}
+
+
+def test_login_submit_rejects_blank_code(client, env):
+    r = client.post("/login/submit", headers=_admin(env), json={"code": ""})
+    assert r.status_code == 422
+
+
+def test_login_start_requires_auth(client):
+    assert client.post("/login/start").status_code in (401, 403)
+
+
+def test_login_endpoints_require_admin_token(client, env, monkeypatch):
+    # With a distinct admin token set, the plain auth token must be refused.
+    monkeypatch.setenv("ADMIN_TOKEN", "admin-secret")
+    from handler import config
+
+    config.get_settings.cache_clear()
+    try:
+        r = client.post("/login/start", headers={"Authorization": f"Bearer {env['token']}"})
+        assert r.status_code == 403
+        ok = client.post("/login/start", headers={"Authorization": "Bearer admin-secret"})
+        assert ok.status_code == 202
+    finally:
+        config.get_settings.cache_clear()