fix: improve MCP page setup UX and remove automation credit quotas (#821)

* Remove MCP credit quotas and improve MCP setup page

- Always show client setup snippets with placeholder keys
- Add View Docs link to MCP page header
- Remove monthly automation credit enforcement and UI
- Update plan feature text to reflect free MCP access

Co-authored-by: Rotimi Best <[email protected]>

* fix: address PR review feedback for MCP page changes

- Clear generatedSecret when revoking MCP keys
- Use Button link mode for View Docs with rel noopener noreferrer
- Update all dashboard locale files for MCP translations
- Make MCP rate-limit admission atomic with transactional reservations
- Wrap MCP route handlers with withMcpAutomationUsage helper

Co-authored-by: Rotimi Best <[email protected]>

* revert: remove atomic MCP rate-limit reservations

The transactional advisory-lock reservation was unnecessary complexity
for our MCP usage model. Restore the simpler check-then-record flow.

Also only clear generatedSecret when revoking the key it belongs to.

Co-authored-by: Rotimi Best <[email protected]>

* fix: address remaining MCP page bot review feedback

- Add blank lines after confirm guards in key handlers
- Skip showing rotated secret if key was revoked during rotation
- Fix vi keys_title and de rate_limits_title translations

Co-authored-by: Rotimi Best <[email protected]>

* fix: prevent late key rotation from un-revoking or exposing secrets

- Rotate only when revoked_at IS NULL at update time (DB)
- Reject rotate requests for already-revoked keys (API)
- Ignore stale rotate responses in automation client state
- Guard MCP UI against showing secrets for revoked keys

Co-authored-by: Rotimi Best <[email protected]>

---------

apps/dashboard/src/lib/utils/translations/de.json

@@ -4081,16 +4081,15 @@
       },
       "usage": {
         "title": "Nutzung und Grenzen",
-        "description": "MCP ist in jedem Plan verfügbar, die Nutzung wird jedoch durch monatliche Automatisierungsguthaben und Schlüssellimits gesteuert.",
-        "credits_title": "Verbleibende Credits",
-        "credits_description": "Mutierende MCP-Aktionen verbrauchen Credits. Leseaktionen sind kostenlos.",
+        "description": "MCP ist in jedem Plan verfügbar. Die Nutzung wird durch Schlüssellimits und Ratenlimits gesteuert.",
         "keys_title": "Aktive Schlüssel",
         "keys_description": "Verwenden Sie einen MCP-Schlüssel pro Integration, damit der Zugriff sauber rotiert oder widerrufen werden kann.",
-        "rate_limits_title": "Tarifbegrenzungen",
+        "rate_limits_title": "Anfragenlimits pro Minute",
         "rate_limits_description": "Zulässige Lese-/Schreib-/Veröffentlichungsanfragen pro Minute.",
         "used_label": "Verwendet:"
       },
-      "page_subtitle": "Verbinden Sie KI-Tools mit ClassroomIO über organisationsbezogene Schlüssel, die Sie jederzeit rotieren können."
+      "page_subtitle": "Verbinden Sie KI-Tools mit ClassroomIO über organisationsbezogene Schlüssel, die Sie jederzeit rotieren können.",
+      "view_docs": "Dokumentation anzeigen"
     },
     "api": {
       "subtitle": "Verwalten Sie API-Schlüssel zur Integration mit der öffentlichen ClassroomIO-API.",