feat(license): metered licensing — catalogue, entitlements, and enforcement

Implements spec 7 tasks 2-10 on top of the six-plan payload from task 1.

Admin: plans re-keyed on (deployment, tier); new catalogue collection holds
every Paddle price ID (one row per priceable component); new entitlements
collection holds desired beside granted. admin/internal/catalogue owns both
folds — entitlement to licence limits, and entitlement to Paddle line items —
so the base allowance is subtracted in exactly one place. licensing.Issue now
snapshots the instance's granted entitlement, never desired. Free is enforced
per account AND deployment. Staff endpoints for plans, catalogue and
entitlements; Free self-hosted can be claimed and renewed on its annual term;
the reaper stays cloud-only.

Server: enforces the monitor cap, audit-log retention (daily sweep, skips
Unlimited and lapsed instances), and gates the OIDC callback. Unset limits are
filled from the seed plan at the single decode site so old blobs never read as
zero.

Frontends: adminsite gains a catalogue price-ID editor, six-plan allowance
screen, and a catalogue-driven PlanConfigurator mounted on the staff instance
page. web shows monitors, audit retention and support level on the licence page.

Docs: CLAUDE.md, spec index and plan 5 preamble updated.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

claude.md

@@ -312,6 +312,8 @@ org          GET,POST /org/users · PUT /org/users/:id/role · DELETE /org/users
 
 `POST /license` is also in `licenceExemptPaths`: pasting a valid licence has to work while the current one is expired, because it is the way out of degraded mode.
 
+Free exists in both deployments, so it is no longer cloud-only by construction. The one-Free-per-account rule is enforced per account **and deployment**, in `licensing.checkFreeLimit` and in `createInstance`'s friendly pre-check — the two must stay scoped identically, because a pre-check stricter than the issuer refuses what would have worked. A self-hosted Free licence is claimed with `POST /api/instances/:id/claim-free` after the install is linked; the metered server count and per-instance feature toggles come from the instance's `entitlement`, which a licence snapshots at issue time (see the `catalogue`/`entitlements` note under MongoDB Collections).
+
 ---
 
 ## Admin REST API (`admin`, :8083)
@@ -331,9 +333,11 @@ Customer-session (`/api`), every instance resolved through `ownedInstance`:
 
 ```
 GET  /account                                  # account, instances, max_relinks
-POST /instances                                # create a cloud instance (Free tier, capped at one per account)
+POST /instances                                # create a cloud instance (Free tier, one Free per account per deployment)
 POST /instances/:id/renew                      # Free renewal; refuses outside the renewal window
+POST /instances/:id/claim-free                 # issue Free on a linked self-hosted instance
 POST /instances/link · /instances/:id/relink
+GET  /instances/:id/entitlement
 GET  /instances/:id/license · /instances/:id/license/download
 GET  /subscriptions
 GET,POST /account/users · PUT /account/users/:id/role · DELETE /account/users/:id
@@ -353,7 +357,9 @@ Staff-session (`/api/staff`):
 GET,POST /accounts · GET /accounts/:id         # search by name, email, Paddle ID or instance UUID
 GET,POST /instances · GET /instances/:id       # instance + account + licence history + injection state
 POST /instances/:id/issue · /instances/:id/relink
-GET  /licenses · /subscriptions · /audit · /plans · PUT /plans/:tier
+GET  /licenses · /subscriptions · /audit · /plans · PUT /plans/:deployment/:tier
+GET,PUT /catalogue
+GET,PUT /instances/:id/entitlement
 GET  /health/injection
 ```
 
@@ -375,7 +381,9 @@ Notes that are not obvious from the structs:
 - `console_sessions.token_consumed_at` is set atomically to enforce one-time use.
 - `users.auth_source` is `local`, `oidc` or `hq`. An `hq` user was projected from a Vantage HQ account and carries `hq_user_id`; HQ owns its role, password and existence.
 
-Admin's own database is separate and holds `accounts` · `admin_instances` · `licenses` · `subscriptions` · `plans` · `staff_users` · `customer_users` · `instance_members` · `admin_audit`. `instance_members` is unique on `(instance_id, customer_user_id)` — one person holds at most one user in one instance, which makes a grant idempotent-by-refusal rather than silently doubling a projection. It is an *index* of the control-plane rows, not the authority (see "Grants project, they do not federate"). Admin has no migrations collection; `models.Backfill` runs on every boot and is idempotent by filtering on the absence of what it writes.
+Admin's own database is separate and holds `accounts` · `admin_instances` · `licenses` · `subscriptions` · `plans` · `catalogue` · `entitlements` · `staff_users` · `customer_users` · `instance_members` · `admin_audit`. `instance_members` is unique on `(instance_id, customer_user_id)` — one person holds at most one user in one instance, which makes a grant idempotent-by-refusal rather than silently doubling a projection. It is an *index* of the control-plane rows, not the authority (see "Grants project, they do not federate"). Admin has no migrations collection; `models.Backfill` runs on every boot and is idempotent by filtering on the absence of what it writes.
+
+`plans` is keyed on `(deployment, tier)` — six rows, two deployments times three tiers — and holds base allowances only. **Every Paddle price ID lives in `catalogue`**, one row per priceable component (`base`, `limit`, `feature`), because a metered plan is priced by several prices and one map on a plan row cannot express that. `entitlements` holds one row per instance with `desired` beside `granted`: the checkout is built from `desired`, a licence is only ever signed from `granted`, and an abandoned checkout therefore leaves a `desired` that reached nothing. The two Free plans have **no catalogue rows at all**, which is what keeps Free outside Paddle.
 
 ### Migrations