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.

.vscode/extensions.json

@@ -0,0 +1,9 @@
+{
+  "recommendations": [
+    "esbenp.prettier-vscode",
+    "dbaeumer.vscode-eslint",
+    "ms-vscode.vscode-typescript-next",
+    "bradlc.vscode-tailwindcss",
+    "dzhavat.mermaid-preview"
+  ]
+}