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- Skip showing rotated secret if key was revoked during rotation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/da.json

@@ -4081,16 +4081,15 @@
       },
       "usage": {
         "title": "Anvendelse og grænser",
-        "description": "MCP er tilgængelig på alle abonnementer, men brugen styres med månedlige automatiseringskreditter og nøglegrænser.",
-        "credits_title": "Kreditter tilbage",
-        "credits_description": "Muterende MCP-handlinger bruger kreditter. Læsehandlinger er gratis.",
+        "description": "MCP er tilgængelig på alle abonnementer. Brugen styres af nøglegrænser og hastighedsgrænser.",
         "keys_title": "Aktive nøgler",
         "keys_description": "Brug én MCP-nøgle pr. integration, så adgang kan roteres eller tilbagekaldes rent.",
         "rate_limits_title": "Satsgrænser",
         "rate_limits_description": "Læs/skriv/publicér anmodninger tilladt pr. minut.",
         "used_label": "Brugt:"
       },
-      "page_subtitle": "Forbind AI-værktøjer til ClassroomIO med organisationsnøgler, du kan rotere når som helst."
+      "page_subtitle": "Forbind AI-værktøjer til ClassroomIO med organisationsnøgler, du kan rotere når som helst.",
+      "view_docs": "Se dokumentation"
     },
     "api": {
       "subtitle": "Administrer API-nøgler til integration med ClassroomIOs offentlige API.",