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/skills/session-compare/SKILL.md

@@ -0,0 +1,89 @@
+---
+description: >
+  Compare two sessions side-by-side using Agent Monitor data — per-model
+  token usage (input/output/cache_read/cache_write + compaction baselines),
+  pricing engine cost breakdowns, workflow intelligence (complexity scores,
+  tool flow transitions, subagent effectiveness), session metadata
+  (thinking_blocks, turn_count, turn_duration_ms, usage_extras), and
+  full event timelines with all 10+ event types.
+---
+
+# Session Compare
+
+Compare two Claude Code sessions side-by-side using Agent Monitor data.
+
+## Input
+
+The user provides: **$ARGUMENTS**
+
+This may be:
+- Two session IDs: "abc123 def456"
+- "best vs worst" — compare highest and lowest productivity sessions
+- "latest 2" — compare the two most recent sessions
+- A session ID + "vs average" — compare one session against the baseline
+
+## Procedure
+
+1. **Identify sessions to compare**:
+   - If two IDs given: fetch both from `http://localhost:4820/api/sessions/{id}`
+   - If "best vs worst": fetch sessions, score by completion + cost efficiency, pick extremes
+   - If "latest 2": `GET /api/sessions?limit=2` (default sort: most recently updated first)
+   - If "vs average": fetch session + compute averages from last 50 sessions
+
+2. **Gather detailed data** for each session:
+   - Session metadata: `GET /api/sessions/{id}`
+   - Events: `GET /api/events?session_id={id}`
+   - Agents: `GET /api/agents?session_id={id}`
+   - Cost: `GET /api/pricing/cost/{id}`
+
+3. **Build comparison**:
+
+   ### Overview Comparison
+   | Metric | Session A | Session B | Difference |
+   |--------|-----------|-----------|-----------|
+   | Status | completed | error | — |
+   | Model | sonnet-4 | sonnet-4 | same |
+   | Duration | 12m 34s | 45m 12s | +32m 38s |
+   | Total Cost | $0.0234 | $0.1456 | +522% |
+   | Events | 45 | 187 | +315% |
+   | Tools Used | 8 | 12 | +4 |
+   | Error Count | 0 | 7 | +7 |
+   | Agents | 2 | 5 | +3 |
+
+   ### Token Comparison
+   | Token Type | Session A | Session B | Difference |
+   |-----------|-----------|-----------|-----------|
+   | Input | N | N | ±N% |
+   | Output | N | N | ±N% |
+   | Cache Read | N | N | ±N% |
+   | Cache Write | N | N | ±N% |
+   | Efficiency | N% | N% | ±N% |
+
+   ### Tool Usage Comparison
+   - Tools unique to Session A
+   - Tools unique to Session B
+   - Shared tools with usage count comparison
+   - Error rate per tool in each session
+
+   ### Timeline Comparison
+   - Side-by-side event timeline
+   - Where sessions diverged in approach
+   - Key decision points that led to different outcomes
+
+   ### Agent Activity Comparison
+   - Agent counts and types
+   - Subagent strategy differences
+   - Agent success rates
+
+4. **Analysis**:
+   - Why one session was more efficient/successful than the other
+   - Key decisions that made the difference
+   - Lessons to apply to future sessions
+
+## Output Format
+
+Present as a side-by-side comparison report with:
+- Executive comparison summary (which session was "better" and why)
+- Structured comparison tables with color-coded differences (green = better, red = worse)
+- A "Lessons Learned" section with actionable takeaways
+- Overall winner declaration with justification