feat(docker): resource templates, GPU, elastic disk, bridge-hooks listener

- One-click "Run in Docker" gains an expandable settings panel with a Template
  picker (Small 2G/1 · Medium 4G/2 default · Large 8G/4 · GPU 8G/4/all) plus
  memory/cpu/gpu/network/image/mount-creds overrides. Any tweak creates a dedicated
  per-case host; the plain checkbox keeps using the shared `default` host.
- GPU passthrough: `gpus` on DockerHost/SessionDocker -> `--gpus <value>` in create
  args (needs the NVIDIA container toolkit). Elastic disk: no `--storage-opt` cap,
  so container storage grows as data flows in.
- CODEMAN_DOCKER_BRIDGE_HOOKS=1: opt-in second listener on the docker bridge gateway
  (auto-detected 172.17.0.1, override CODEMAN_DOCKER_BRIDGE_HOST) that serves ONLY
  the hook endpoints and delegates into the secret-gated pipeline, so in-container
  hooks fire on a loopback-only server. Non-hook paths -> 403; host-internal, not LAN.

Verified live: Large template applies real 8GB/4CPU limits; a secret-authenticated
hook POST from inside a container now reaches the handler (was connection-refused);
non-hook paths return 403; template UI + GPU field verified via Playwright.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/docker-hosts.ts

@@ -179,6 +179,7 @@ export function dockerConfigHash(
     | 'network'
     | 'networkName'
     | 'resources'
+    | 'gpus'
     | 'mountCredentials'
     | 'extraCreateArgs'
   >
@@ -190,6 +191,7 @@ export function dockerConfigHash(
     network: docker.network,
     networkName: docker.networkName ?? null,
     resources: docker.resources ?? null,
+    gpus: docker.gpus ?? null,
     mountCredentials: docker.mountCredentials,
     extraCreateArgs: docker.extraCreateArgs ?? null,
   });
@@ -215,6 +217,7 @@ export function toSessionDocker(host: DockerHost, dockerCase: DockerCase): Sessi
     network: host.network ?? 'bridge',
     networkName: host.networkName,
     resources: host.resources ?? DEFAULT_DOCKER_RESOURCES,
+    gpus: host.gpus,
     mountCredentials: host.mountCredentials ?? true,
     hooksEnabled: host.hooksEnabled ?? true,
     resumeOnStart: host.resumeOnStart ?? true,
@@ -360,6 +363,10 @@ export function buildDockerCreateArgs(ctx: DockerCreateContext): string[] {
 
   args.push(
     ...resourceFlags(docker.resources),
+    // GPU passthrough (needs the NVIDIA container toolkit on the host). No storage
+    // cap is set, so the container's writable layer + volumes grow elastically as
+    // data flows in (bounded only by host disk).
+    ...(docker.gpus ? ['--gpus', shellescape(docker.gpus)] : []),
     '--cap-drop',
     'ALL',
     '--security-opt',
@@ -545,6 +552,29 @@ export async function checkDockerTmuxAvailable(
   }
 }
 
+/**
+ * Resolve the host's IP on the default docker bridge (the address a container
+ * reaches as `host.docker.internal`), so the server can bind a hooks-only listener
+ * there and in-container hooks can call back. Defaults to the conventional
+ * 172.17.0.1 when the inspect fails but docker is up; null when docker is absent.
+ * No-op canned value under VITEST.
+ */
+export async function detectDockerBridgeGateway(engine: DockerEngine = 'docker'): Promise<string | null> {
+  if (IS_TEST_MODE) return '172.17.0.1';
+  const bin = engine === 'podman' ? 'podman' : 'docker';
+  try {
+    const { stdout } = await execFileAsync(
+      bin,
+      ['network', 'inspect', 'bridge', '--format', '{{(index .IPAM.Config 0).Gateway}}'],
+      { timeout: DOCKER_PROBE_TIMEOUT_MS }
+    );
+    const ip = stdout.trim();
+    return /^\d{1,3}(\.\d{1,3}){3}$/.test(ip) ? ip : '172.17.0.1';
+  } catch {
+    return null; // docker not available — nothing to bind
+  }
+}
+
 /**
  * Instance-scoped boot reaper: `docker rm -f` any MANAGED container that belongs
  * to THIS instance (by the `codeman.instance` label) but whose case is no longer