feat: add resumable stream support for agent chat (#19107)

## Overview
Add resumable stream support for agent chat to allow clients to
reconnect and resume streaming responses if the connection is
interrupted (e.g., during page refresh).

## Changes

### Backend (Twenty Server)
- Add `activeStreamId` column to `AgentChatThreadEntity` to track
ongoing streams
- Create `AgentChatResumableStreamService` to manage Redis-backed
resumable streams using the `resumable-stream` library with ioredis
- Extend `AgentChatController` with:
  - `GET /:threadId/stream` endpoint to resume an existing stream
  - `DELETE /:threadId/stream` endpoint to stop an active stream
- Update `AgentChatStreamingService` to store streams in Redis and track
active stream IDs
- Add `resumable-stream@^2.2.12` dependency to package.json

### Frontend (Twenty Front)
- Update `useAgentChat` hook to:
- Use a persistent transport with `prepareReconnectToStreamRequest` for
resumable streams
  - Export `resumeStream` function from useChat
  - Add `handleStop` callback to clear active stream on DELETE endpoint
- Use thread ID as stable message ID instead of including message count
- Add stream resumption logic in `AgentChatAiSdkStreamEffect` component
to automatically call `resumeStream()` when switching threads

## Database Migration
New migration `1774003611071-add-active-stream-id-to-agent-chat-thread`
adds the `activeStreamId` column to store the current resumable stream
identifier.

---------

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

.github/workflows/ci-breaking-changes.yaml

@@ -86,6 +86,8 @@ jobs:
         run: |
           echo "Attempting to merge main into current branch..."
 
+          git config user.email "ci@twenty.com"
+          git config user.name "CI"
           git fetch origin main
 
           CURRENT_BRANCH=$(git rev-parse --abbrev-ref HEAD)
@@ -99,8 +101,8 @@ jobs:
             echo "❌ Merge failed due to conflicts"
             echo "⚠️ Falling back to comparing current branch against main without merge"
 
-            # Abort the failed merge
-            git merge --abort
+            # Abort the failed merge (may not exist if merge never started)
+            git merge --abort 2>/dev/null || true
 
             echo "merged=false" >> $GITHUB_OUTPUT
             echo "BRANCH_STATE=conflicts" >> $GITHUB_ENV
@@ -402,6 +404,23 @@ jobs:
           # Clean up temp directory
           rm -rf /tmp/current-branch-files
 
+      - name: Validate downloaded schema files
+        id: validate-schemas
+        run: |
+          valid=true
+
+          for file in main-schema-introspection.json current-schema-introspection.json \
+                      main-metadata-schema-introspection.json current-metadata-schema-introspection.json \
+                      main-rest-api.json current-rest-api.json \
+                      main-rest-metadata-api.json current-rest-metadata-api.json; do
+            if [ ! -f "$file" ] || ! jq empty "$file" 2>/dev/null; then
+              echo "::warning::Invalid or missing schema file: $file"
+              valid=false
+            fi
+          done
+
+          echo "valid=$valid" >> $GITHUB_OUTPUT
+
       - name: Login to Docker Hub
         uses: docker/login-action@v3
         with:
@@ -414,6 +433,7 @@ jobs:
           echo "Using OpenAPITools/openapi-diff via Docker"
 
       - name: Generate GraphQL Schema Diff Reports
+        if: steps.validate-schemas.outputs.valid == 'true'
         run: |
           echo "=== INSTALLING GRAPHQL INSPECTOR CLI ==="
           npm install -g @graphql-inspector/cli
@@ -424,7 +444,6 @@ jobs:
           echo "Checking GraphQL schema for changes..."
           if graphql-inspector diff main-schema-introspection.json current-schema-introspection.json >/dev/null 2>&1; then
             echo "✅ No changes in GraphQL schema"
-            # Don't create a diff file for no changes
           else
             echo "⚠️ Changes detected in GraphQL schema, generating report..."
             echo "# GraphQL Schema Changes" > graphql-schema-diff.md
@@ -442,7 +461,6 @@ jobs:
           echo "Checking GraphQL metadata schema for changes..."
           if graphql-inspector diff main-metadata-schema-introspection.json current-metadata-schema-introspection.json >/dev/null 2>&1; then
             echo "✅ No changes in GraphQL metadata schema"
-            # Don't create a diff file for no changes
           else
             echo "⚠️ Changes detected in GraphQL metadata schema, generating report..."
             echo "# GraphQL Metadata Schema Changes" > graphql-metadata-diff.md
@@ -461,6 +479,7 @@ jobs:
           ls -la *-diff.md 2>/dev/null || echo "No diff files generated (no changes detected)"
 
       - name: Check REST API Breaking Changes
+        if: steps.validate-schemas.outputs.valid == 'true'
         run: |
           echo "=== CHECKING REST API FOR BREAKING CHANGES ==="
 
@@ -529,6 +548,7 @@ jobs:
           fi
 
       - name: Check REST Metadata API Breaking Changes
+        if: steps.validate-schemas.outputs.valid == 'true'
         run: |
           echo "=== CHECKING REST METADATA API FOR BREAKING CHANGES ==="