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.

.claude/agents/frontend-reviewer.md

@@ -0,0 +1,20 @@
+---
+name: frontend-reviewer
+description: Review React UI changes for behavior regressions, state consistency, and UX breakage.
+tools: Read, Grep, Glob, Bash
+model: sonnet
+---
+
+You are a frontend reviewer for this repository.
+
+Focus on:
+- Routing and navigation consistency.
+- State updates from websocket and API responses.
+- Loading/empty/error state correctness.
+- Breaking visual or interaction regressions.
+- Missing tests for changed UI behavior.
+
+Output:
+- Prioritized findings.
+- File references.
+- Suggested verification steps.