ci: restrict to Migrations service for fast feedback loop (TEMP)

Branch is iterating on utopia-php/migration's re-migration tolerance.
Other test matrices (unit, general, abuse, screenshots, benchmark, and
every other e2e service) add ~30+ minutes to CI without exercising code
this PR touches. Restrict the matrix to the Migrations service and skip
the unrelated test jobs until the migration work is ready to merge.

All jobs marked with 'TEMP:' comments + 'if: false' — revert to the
full matrix before merging to main.

Static analysis (lint, phpstan, composer audit, specs, locale, security)
still runs on every PR push.

.github/workflows/ci.yml

@@ -285,6 +285,8 @@ jobs:
 
   unit:
     name: Tests / Unit
+    # TEMP: Migrations-only CI run. Re-enable before merging to main.
+    if: false
     runs-on: ubuntu-latest
     needs: build
     permissions:
@@ -332,6 +334,8 @@ jobs:
 
   e2e_general:
     name: Tests / E2E / General
+    # TEMP: Migrations-only CI run. Re-enable before merging to main.
+    if: false
     runs-on: ubuntu-latest
     needs: build
     permissions:
@@ -400,32 +404,10 @@ jobs:
       matrix:
         database: ${{ fromJSON(needs.matrix.outputs.databases) }}
         mode: ${{ fromJSON(needs.matrix.outputs.modes) }}
-        service: [
-          Account,
-          Avatars,
-          Console,
-          Databases,
-          TablesDB,
-          Functions,
-          FunctionsSchedule,
-          GraphQL,
-          Health,
-          Locale,
-          Projects,
-          Realtime,
-          Sites,
-          Proxy,
-          Storage,
-          Tokens,
-          Teams,
-          Users,
-          ProjectWebhooks,
-          Webhooks,
-          VCS,
-          Messaging,
-          Migrations,
-          Project
-        ]
+        # TEMP: branch is testing utopia-php/migration re-migration tolerance.
+        # Restricted to Migrations to get fast CI feedback on the feature work;
+        # revert to the full matrix before merging to main.
+        service: [Migrations]
         include:
           - service: Databases
             runner: blacksmith-4vcpu-ubuntu-2404
@@ -524,6 +506,8 @@ jobs:
 
   e2e_abuse:
     name: Tests / E2E / Abuse (${{ matrix.mode }})
+    # TEMP: Migrations-only CI run. Re-enable before merging to main.
+    if: false
     runs-on: ubuntu-latest
     needs: [build, matrix]
     permissions:
@@ -583,6 +567,8 @@ jobs:
 
   e2e_screenshots:
     name: Tests / E2E / Screenshots (${{ matrix.mode }})
+    # TEMP: Migrations-only CI run. Re-enable before merging to main.
+    if: false
     runs-on: ubuntu-latest
     needs: [build, matrix]
     permissions:
@@ -649,6 +635,8 @@ jobs:
 
   benchmark:
     name: Benchmark
+    # TEMP: Migrations-only CI run. Re-enable before merging to main.
+    if: false
     runs-on: ubuntu-latest
     needs: build
     permissions: