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-insights/commands/compare.md

@@ -0,0 +1,26 @@
+---
+description: Compare two sessions side-by-side with cost and workflow deltas
+argument-hint: "[sessionA] [sessionB]"
+---
+
+Compare the two sessions in **$ARGUMENTS** (first id = Session A, second id = Session B) side-by-side using the Agent Monitor dashboard. If fewer than two ids are given, ask for both.
+
+1. Fetch cost for each, in parallel:
+   - `curl -s http://localhost:4820/api/pricing/cost/<sessionA>`
+   - `curl -s http://localhost:4820/api/pricing/cost/<sessionB>`
+   Each returns `{ total_cost, breakdown:[{ model, input_tokens, output_tokens, cache_read_tokens, cache_write_tokens, cost, matched_rule }] }`.
+
+2. Fetch workflow intelligence for each:
+   - `curl -s http://localhost:4820/api/workflows/<sessionA>`
+   - `curl -s http://localhost:4820/api/workflows/<sessionB>`
+   Use `stats` (tool/event/agent counts), `complexity` (score), `effectiveness` (subagent success), `compaction` (impact), and `errorPropagation`.
+
+3. Print a side-by-side comparison table with a delta column (B − A):
+   - Total cost (USD, 4 decimals) and Δ% .
+   - Tokens: input, output, cache_read, cache_write (sum the breakdown per session).
+   - Cache hit rate = `cache_read / (cache_read + input)`.
+   - Tool count, event count, agent count (from `stats`).
+   - Complexity score (from `complexity`).
+   - Subagent success rate (from `effectiveness`) and compaction count (from `compaction`).
+
+Output rules: one row per metric with columns Session A | Session B | Δ; use ▲ when B is higher and ▼ when lower; currency in USD to 4 decimals; rates as percentages to 2 decimals. End with a one-line verdict on which session was cheaper/leaner and the main driver. Cite only fields the API returned — never fabricate. If a session id is unknown or the dashboard is unreachable at `http://localhost:4820`, say so and tell the user to start it with `npm start` from the repo root.