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/data/profile-templates/postgres-compose/hooks/db-create.sh

@@ -3,13 +3,13 @@
 # db-create.sh – Create this lane's Postgres database inside a docker-compose
 # service, via `createdb`. Ported verbatim from Shipyard's own lane-bootstrap
 # / lane-up / lane-reset scripts, so a Postgres-via-compose repo gets parity
-# by copying this template into its own .ccam/profile/hooks/.
+# by copying this template into its own .agenthub/profile/hooks/.
 #
 # Called as: db-create.sh <db-name>  (also available as $DB_NAME)
 # Requires, declared in the repo's own profile.env:
 #   COMPOSE_FILE   path to the docker-compose file (e.g. "$LANE_DIR/docker-compose.yml")
 #   DB_SERVICE     the compose service name running Postgres
-# Provided by CCAM's hook environment (server/lib/secrets.js):
+# Provided by AgentHub's hook environment (server/lib/secrets.js):
 #   PG_USER        (PG_PASS is deliberately not exported — trust auth inside the
 #                    compose network needs no password for this call)
 # ─────────────────────────────────────────────────────────────────────────────

server/data/profile-templates/postgres-compose/hooks/db-drop.sh

@@ -2,7 +2,7 @@
 # ─────────────────────────────────────────────────────────────────────────────
 # db-drop.sh – Drop this lane's Postgres database inside a docker-compose
 # service, via `dropdb --if-exists`. Ported verbatim from Shipyard's own
-# lane-reset / lane-remove scripts. CCAM only ever calls this with a name it
+# lane-reset / lane-remove scripts. AgentHub only ever calls this with a name it
 # derived itself (server/lib/lane-services.js:dropDatabase), so this script
 # never needs to re-validate its argument.
 #