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.

.codex/skills/mcp-maintainer/references/operations-runbook.md

@@ -0,0 +1,14 @@
+# MCP Operations Runbook
+
+## Modes
+- Read-only:
+  - `MCP_DASHBOARD_ALLOW_MUTATIONS=false`
+  - `MCP_DASHBOARD_ALLOW_DESTRUCTIVE=false`
+- Admin:
+  - Set mutations true for controlled maintenance operations.
+- Destructive:
+  - Set both true and require `confirmation_token = CLEAR_ALL_DATA`.
+
+## Verification
+- `npm run mcp:typecheck`
+- `npm run mcp:build`