feat: Claude Code Monitor — lanes, pipelines and a merged workspace

Internal SmartGift build of a Claude Code monitoring dashboard.

Lanes: a durable unit of parallel agent work, one per working directory,
tracked across session restarts. Managed lanes are git worktrees the
dashboard provisions and can reset or remove behind a three-check destroy
guard and a counted preflight; adopted lanes are directories you already
own and are never destroyable.

Pipelines: a lane moves through pipeline stages. A stage the agent declares
with evidence renders green; a stage inferred from the tool-event stream
renders dashed amber and never counts as done. Detection is forward-only
within a 30-minute window, and never writes the declared stage.

Workspace: one page at /run with a lane grid, the selected lane's pipeline,
and a full Claude console behind a disclosure.

plugins/ccam-dashboard/commands/ping.md

@@ -0,0 +1,30 @@
+---
+description: Check Agent Monitor reachability and print UP/DOWN with latency
+---
+
+Check whether the dashboard API is reachable and report latency.
+
+Run:
+
+```bash
+curl -s -o /dev/null -m 5 -w '%{http_code} %{time_total}s' http://localhost:4820/api/stats
+```
+
+`%{http_code}` is the HTTP status and `%{time_total}` is the total round-trip
+time in seconds.
+
+Print one line:
+
+- If the request succeeds with a 2xx status:
+  ```
+  ✅ UP | http://localhost:4820/api/stats | 200 | 0.042s
+  ```
+  (use the real status code and the real latency, converting seconds to ms if
+  clearer, e.g. `42ms`).
+
+- If `curl` exits non-zero (connection refused/timeout) or the status is not 2xx:
+  ```
+  ❌ DOWN | http://localhost:4820/api/stats unreachable — start it with `npm start` (or `npm run dev`) from the repo root
+  ```
+
+Output only the single line — no preamble. Do not modify any data.