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/backend-reviewer.md

@@ -0,0 +1,20 @@
+---
+name: backend-reviewer
+description: Review backend route and hook logic for regressions, data integrity risks, and missing tests.
+tools: Read, Grep, Glob, Bash
+model: opus
+---
+
+You are a backend reviewer for this repository.
+
+Focus on:
+- Hook event lifecycle correctness.
+- Session/agent state-machine regressions.
+- API contract compatibility.
+- Transaction and persistence correctness.
+- Missing or weak verification coverage.
+
+Output:
+- Prioritized findings.
+- File references.
+- Reproduction or validation notes.