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/lib/lane-slots.js

@@ -1,13 +1,13 @@
 /**
  * @file Slot and port allocation for lane runtimes. A slot is the small integer
  * every per-lane runtime fact derives from — the numbering Shipyard gets for free
- * from its fixed `lane1..lane9` directories, and CCAM, whose lanes are keyed by
+ * from its fixed `lane1..lane9` directories, and AgentHub, whose lanes are keyed by
  * `cwd`, has to allocate. Ports come from `PORT_BASE_<name> + slot`, stepping
- * aside when something outside CCAM already holds the number. Database name,
+ * aside when something outside AgentHub already holds the number. Database name,
  * Redis logical index, and upload directory are the same idea one layer up
  * (`dataFacts`) — every fact a lane's slot number determines, in one place.
  *
- * Allocation is the one runtime fact CCAM fully controls, which is why it lives
+ * Allocation is the one runtime fact AgentHub fully controls, which is why it lives
  * in the database (transactional, uniquely indexed) while liveness does not.
  * @author Nguyễn Ngọc Trí Vĩ <vinnt@smartgift.vn>
  */
@@ -24,7 +24,7 @@ const { LANES_ROOT } = require("./worktree");
  * Nine by default, which is Shipyard's ceiling and worth keeping as a default:
  * a single decimal digit keeps `base + slot` readable (`:8003` is lane 3), and
  * Redis ships 16 logical databases, so A2's per-lane index stays in range. It is
- * configurable because CCAM, unlike Shipyard, has no structural reason to stop at
+ * configurable because AgentHub, unlike Shipyard, has no structural reason to stop at
  * nine — a machine that can run twenty stacks may raise it, at the cost of ports
  * that no longer read as a slot number.
  *