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).

server/routes/lanes.js

@@ -562,8 +562,8 @@ router.post("/:id/mcp/sync", sameOriginGuard, async (req, res) => {
 
 /**
  * Detect a Node.js project at this lane's OWN directory and scaffold
- * .ccam/profile/ if one is found — the HTTP equivalent of
- * `ccam lanes profile init`, always targeting lane.cwd (never an arbitrary
+ * .agenthub/profile/ if one is found — the HTTP equivalent of
+ * `agenthub lanes profile init`, always targeting lane.cwd (never an arbitrary
  * path; the CLI's <repo> argument has no meaning here, this lane's own
  * directory is the only sensible target). "No Node.js project detected" is
  * a normal 200 outcome, not an error — most lanes won't be auto-detectable
@@ -590,7 +590,7 @@ router.post("/:id/profile/init", sameOriginGuard, (req, res) => {
 
 /**
  * Whether a named integration (tracker, dev_qc, ci_wait, ...) is turned on
- * for this lane — reads .ccam/profile/integrations.env. Read-only, no
+ * for this lane — reads .agenthub/profile/integrations.env. Read-only, no
  * sameOriginGuard needed (same reasoning GET /:id/git already documents:
  * that guard exists for destructive actions).
  */
@@ -628,7 +628,7 @@ router.get("/:id/git", async (req, res) => {
 /**
  * A single GitHub Actions status snapshot for one ref (branch or commit sha)
  * in the lane's repo — NOT a poll loop. ship-feature-lane's Stage 13 owns
- * the wait/retry decision (docs/LANES.md "Orchestration: what CCAM does NOT
+ * the wait/retry decision (docs/LANES.md "Orchestration: what AgentHub does NOT
  * do"); this route only reports what `gh` currently knows. Read-only, no
  * same-origin guard, same reasoning as GET /:id/git.
  */