[SDK] Refactor clients (#18433)

# Intoduction

Closes https://github.com/twentyhq/core-team-issues/issues/2289

In this PR all the clients becomes available under `twenty-sdk/clients`,
this is a breaking change but generated was too vague and thats still
the now or never best timing to do so

## CoreClient
The core client is now shipped with a default stub empty class for both
the schema and the client
Allowing its import, will still raises typescript errors when consumed
as generated but not generated

## MetadataClient
The metadata client is workspace agnostic, it's now generated and
commited in the repo. added a ci that prevents any schema desync due to
twenty-server additions

Same behavior than for the twenty-front generated graphql schema

.github/workflows/ci-server.yaml

@@ -25,6 +25,7 @@ jobs:
         packages/twenty-server/**
         packages/twenty-front/src/generated/**
         packages/twenty-front/src/generated-metadata/**
+        packages/twenty-sdk/src/clients/generated/metadata/**
         packages/twenty-emails/**
         packages/twenty-shared/**
 
@@ -158,8 +159,10 @@ jobs:
 
             exit 1
           fi
-      - name: GraphQL / Check for Pending Generation
+      - name: Check for Pending Code Generation
         run: |
+          HAS_ERRORS=false
+
           npx nx run twenty-front:graphql:generate
           npx nx run twenty-front:graphql:generate --configuration=metadata
 
@@ -171,11 +174,25 @@ jobs:
             git diff -- packages/twenty-front/src/generated packages/twenty-front/src/generated-metadata
             echo "==================================================="
             echo ""
-            echo "Please run 'npx nx run twenty-front:graphql:generate' and 'npx nx run twenty-front:graphql:generate --configuration=metadata' and commit the changes."
-            echo ""
-            exit 1
+            HAS_ERRORS=true
           fi
 
+          npx nx run twenty-sdk:generate-metadata-client
+
+          if ! git diff --quiet -- packages/twenty-sdk/src/clients/generated/metadata; then
+            echo "::error::SDK metadata client changes detected. Please run 'npx nx run twenty-sdk:generate-metadata-client' and commit the changes."
+            echo ""
+            echo "The following SDK metadata client changes were detected:"
+            echo "==================================================="
+            git diff -- packages/twenty-sdk/src/clients/generated/metadata
+            echo "==================================================="
+            echo ""
+            HAS_ERRORS=true
+          fi
+
+          if [ "$HAS_ERRORS" = true ]; then
+            exit 1
+          fi
   server-test:
     needs: server-build
     timeout-minutes: 30