refactor!: rebrand CCAM to AgentHub

Clean break, no compatibility alias. Renames the product name, the CLI
binary (`ccam` -> `agenthub`), the env var prefix (`CCAM_` ->
`AGENTHUB_`), the Prometheus metric namespace (`ccam_*` ->
`agenthub_*`), the tmux session prefix (`ccam-lane-<id>` ->
`agenthub-lane-<id>`), the per-repo runtime profile directory
(`.ccam/profile` -> `.agenthub/profile`), the lanes state root
(`~/.claude/ccam-lanes` -> `~/.claude/agenthub-lanes`), the bundled
plugins (`plugins/ccam*` -> `plugins/agenthub*`) and their slash
commands (`/ccam-doctor` -> `/agenthub-doctor`, `/ccam:*` ->
`/agenthub:*`).

Because there is no alias, an existing install has to be updated by
hand: rename its `.ccam/profile` directory and any `CCAM_*` variables,
and reinstall the plugin under its new name.

Two other name families are deliberately left alone here, since they are
not just strings: the `Claude-Code-Monitor` repository/marketplace name,
and the `agent-dashboard` npm package plus its `~/.claude/agent-dashboard`
runtime directory, which holds the live database and needs a migration
rather than a rename.

Verified: server 1406/1406, client 459/459, `grep -i ccam` clean across
tracked files, `openapi.yaml` regenerated (95 paths, unchanged count).

plugins/agenthub-quality/commands/health.md

@@ -0,0 +1,31 @@
+---
+description: One-line reliability verdict (OK / DEGRADED / FAILING) for Claude Code usage
+---
+
+Print a single reliability verdict for Claude Code usage from the Agent Monitor
+dashboard at `http://localhost:4820`. No arguments.
+
+1. Fetch state:
+   ```bash
+   curl -s http://localhost:4820/api/stats
+   curl -s http://localhost:4820/api/analytics
+   ```
+   From `stats`: `total_events`, `events_today`, `sessions_by_status`. From
+   `analytics`: `event_types` (PreToolUse, PostToolUse, APIError).
+
+2. Derive two reliability signals:
+   - **Error rate** = `APIError / total_events` (percentage, 2 decimals).
+   - **Tool-failure rate** = `(PreToolUse − PostToolUse) / PreToolUse` (percentage).
+
+3. Pick the verdict from the worse of the two signals:
+   - **OK** — error rate ≤ 1% and tool-failure rate ≤ 1%.
+   - **DEGRADED** — either is in 1–5%.
+   - **FAILING** — either exceeds 5%.
+
+4. Print exactly one line:
+   `Reliability: <OK|DEGRADED|FAILING> — errors X.XX%, tool failures Y.YY% (N events)`
+   Prefix with ✅ (OK), ⚠️ (DEGRADED), or ❌ (FAILING).
+
+Output rules: cite only fields the API returned — never fabricate. One line only;
+no extra prose. If `curl` cannot reach `http://localhost:4820`, print
+`Reliability: UNKNOWN — dashboard unreachable; start it with \`npm start\` from the repo root.`