Node-placed agent terminal: container PTY on the agent's node + WebRTC, shared node-local drives

Completes "agent on a node" (single-node): when an agent's placement points at a
fleet node, its terminal container runs there and the browser reaches it over a
direct WebRTC DataChannel (LAN speed), sharing a node-local volume with the
sandbox. gw-04-local agents are byte-identical to before.

- cm-sandbox/docker.rs: empty drive subpath → mount the whole volume at the target
  (volume_options None), so a per-agent node-local volume auto-creates at ~/drives.
- cm-api/fleet.rs: NodeHub.open_pty/webrtc_offer carry optional container+session
  (injected only when Some); node-terminal caller passes None (host shell unchanged).
- cm-runtime/terminals.rs: TerminalManager gains node_provider + placement
  (mirrors SandboxManager, draining-aware); node_local_drive_mount(agent) =
  clawmates_agent_<id> at ~/drives; placement_for() ensures + locates the container;
  attach uses driver_for(node) (local byte-identical).
- cm-runtime/sandboxes.rs: a node-placed agent sandbox mounts the same per-agent
  volume → shares files with the terminal on that node.
- cm-api/routes/terminal.rs: ticket response gains `node`; ws() bridges node-placed
  agents through the NodeHub relay (WebRTC + fallback) execing into the container;
  local path unchanged. server main wires with_node_provider.
- frontend: agentTerminalConnector mints the ticket then picks WebRTC (node-placed,
  ⚡ direct / relayed badge) vs WS (local); webrtcConnector generalized to be
  endpoint-agnostic (node terminal reuses it).

Known follow-up: terminal (uid 65532) and sandbox (uid 10001) share the volume but
differ in uid — cross-container writes need an aligned uid/gid (group-writable).

Co-Authored-By: Claude Opus 4.8 (1M context) <[email protected]>

crates/bins/clawmates-server/src/main.rs

@@ -185,14 +185,21 @@ async fn run() -> Result<(), String> {
                 } else {
                     None
                 };
-                let terminals = std::sync::Arc::new(cm_runtime::TerminalManager::new(
-                    driver,
-                    pool.clone(),
-                    "local",
-                    &config.sandbox.terminal_image,
-                    config.sandbox.terminal_egress,
-                    drives,
-                ));
+                let terminals = std::sync::Arc::new(
+                    cm_runtime::TerminalManager::new(
+                        driver,
+                        pool.clone(),
+                        "local",
+                        &config.sandbox.terminal_image,
+                        config.sandbox.terminal_egress,
+                        drives,
+                    )
+                    // An agent placed on a fleet node runs its terminal there too
+                    // (beside its sandbox), sharing the agent's node-local drives.
+                    .with_node_provider(std::sync::Arc::new(
+                        cm_api::fleet::HubDriverProvider::new(node_hub.clone()),
+                    )),
+                );
                 // Boot reconciliation: any sandbox the engine still holds is an
                 // orphan from a dead process (we track none yet) — remove them
                 // before warming so a crash/redeploy can't leak containers.