feat(pricing): collapse to two tiers (#1309)

* feat(pricing): collapse to two tiers (Community + Admiral)

Collapse Sencho's pricing from three tiers (Community / Skipper / Admiral)
to two: a generous free Community tier and a single paid Admiral tier. The
Skipper tier is removed.

Now free in Community: auto-heal, auto-update, scheduled operations,
webhooks, notification routing, Fleet Actions and bulk operations, SSO
preset providers (Google / GitHub / Okta), unlimited users with admin and
viewer roles, and deploy safety (atomic deploys, auto-rollback, and
one-click rollback).

Admiral (paid) is focused on running and governing a fleet: blueprints,
Fleet Secrets, deploy enforcement, vulnerability report export, audit log,
host console, private registries, mesh networking, node cordon, managed
cloud backup, LDAP / Active Directory SSO, and the advanced RBAC roles
(deployer, node-admin, auditor) with per-resource scoped assignments.

Internally the license variant distinction is removed so tier is binary
(community / paid). License validation still verifies the Lemon Squeezy
store and product before granting paid status.

Docs and the contributor guide are updated to the two-tier model.

* docs(pricing): correct licensing page to two-tier pricing and tidy stale tier wording

The licensing docs page kept the old Admiral pricing plus a Founder
Lifetime column and an Enterprise paragraph after the two-tier collapse.
Update it to $12/month or $99/year, drop the lifetime and Enterprise
content, and link to the pricing page for current pricing.

Also fix stale "Skipper" wording in CLA.md, SUPPORT.md, one test title,
and three test comments. Historical CHANGELOG entries and the
retired-Skipper license-guard test are intentionally left as-is.

* docs: align licensing and SSO pages with the two-tier model

Correct the SSO overview so the Google, GitHub, and Okta presets read as
available on every tier, matching the provider table; only LDAP and Active
Directory require Sencho Admiral. Remove the lifetime-plan references from the
licensing, settings, and troubleshooting pages so they reflect subscription-only
Admiral pricing.

* fix(rbac): omit scoped permissions from /me on the Community tier

Scoped role assignments only take effect on the paid tier, but GET /api/permissions/me returned them unconditionally, so a downgraded instance with leftover assignments rendered per-resource affordances the API then rejected with 403. The endpoint now mirrors the permission middleware and includes scoped permissions only on the paid tier. Adds a regression test covering the downgrade case.

* docs: use custom-pricing wording on the contact page

The two-tier model has no Enterprise tier; reword the contact page's enterprise pricing/deals to custom pricing/deals so it does not imply a tier that no longer exists.

docs/api-reference/overview.mdx

@@ -67,8 +67,7 @@ The `code` field is present for specific error types:
 
 | Code | Meaning |
 |------|---------|
-| `PAID_REQUIRED` | Endpoint requires a Skipper or Admiral license |
-| `ADMIRAL_REQUIRED` | Endpoint requires an Admiral license |
+| `PAID_REQUIRED` | Endpoint requires an Admiral license |
 | `SCOPE_DENIED` | API token scope does not allow this operation |
 
 ## Input validation
@@ -117,10 +116,9 @@ Some endpoints are gated by license tier:
 
 | Tier | Gated features |
 |------|---------------|
-| **Skipper+** | Webhooks, Fleet snapshots, Stack rollback |
-| **Admiral** | Scheduled Tasks |
+| **Admiral** | Scan policies, Private registries |
 
-Requests to gated endpoints on a lower tier return `403` with the appropriate error code.
+Requests to gated endpoints on Community return `403` with the `PAID_REQUIRED` error code.
 
 ## WebSocket endpoints
 

docs/api-reference/security.mdx

@@ -5,7 +5,7 @@ description: Automate scan policies, CVE suppressions, and vulnerability scans f
 
 The Security API lets you manage scan policies, CVE suppressions, and trigger vulnerability scans from CI pipelines and automation scripts. Every endpoint in this reference is intended for external automation; internal frontend-only endpoints (finding listings, SARIF downloads) are not documented here.
 
-All endpoints require [Bearer token authentication](/api-reference/overview#authentication). Manual scans, secret and misconfiguration results, scan comparison, and CVE suppressions are available on every tier. Scan policies (with `block_on_deploy` enforcement), SBOM, and SARIF stay on Skipper or Admiral. See the per-endpoint **License** row for details.
+All endpoints require [Bearer token authentication](/api-reference/overview#authentication). Manual scans, secret and misconfiguration results, scan comparison, and CVE suppressions are available on every tier. Scan policies (with `block_on_deploy` enforcement), SBOM, and SARIF require Admiral. See the per-endpoint **License** row for details.
 
 ## Scan policies
 
@@ -17,7 +17,7 @@ Writes are admin-only and rejected on replica nodes (policies are managed on the
 
 **`GET /api/security/policies`**
 
-**License:** Skipper or Admiral
+**License:** Admiral
 
 ```bash
 curl -H "Authorization: Bearer YOUR_API_TOKEN" \
@@ -48,7 +48,7 @@ curl -H "Authorization: Bearer YOUR_API_TOKEN" \
 
 **`POST /api/security/policies`**
 
-**License:** Skipper or Admiral · **Role:** Admin
+**License:** Admiral · **Role:** Admin
 
 | Field | Type | Required | Description |
 |-------|------|:--------:|-------------|
@@ -84,7 +84,7 @@ curl -X POST https://your-sencho-instance:1852/api/security/policies \
 
 **`PUT /api/security/policies/{id}`**
 
-**License:** Skipper or Admiral · **Role:** Admin
+**License:** Admiral · **Role:** Admin
 
 Any of the create fields can be updated individually. Omitted fields are left unchanged.
 
@@ -103,7 +103,7 @@ curl -X PUT https://your-sencho-instance:1852/api/security/policies/1 \
 
 **`DELETE /api/security/policies/{id}`**
 
-**License:** Skipper or Admiral · **Role:** Admin
+**License:** Admiral · **Role:** Admin
 
 ```bash
 curl -X DELETE https://your-sencho-instance:1852/api/security/policies/1 \