Move i18n workflow from single-PRs to release PRs (#5225)

* [feat] Move i18n workflow to release-only pattern

- Modify i18n.yaml to only run on version-bump-* branches and manual dispatch
- Follow chromatic.yaml pattern for release-only workflows
- Update CONTRIBUTING.md to document new translation process
- Reduces PR conflicts and improves development velocity

Fixes #5224

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

* [feat] Optimize i18n workflow trigger conditions

Move logic from job-level 'if' to more restrictive trigger configuration:
- Limit pull_request trigger to main/master branches only
- Add explicit types to reduce unnecessary workflow runs
- Simplify job-level condition while maintaining same behavior
- Only run on version-bump-* branches or manual dispatch

* Apply suggestion from @DrJKL

Co-authored-by: Alexander Brown <drjkl@comfy.org>

* [feat] Optimize i18n workflow trigger conditions

- Simplify trigger section with cleaner organization
- Move workflow_dispatch to top for better readability
- Remove unnecessary path-ignore filters
- Add clearer comments for branch detection logic
- Maintain same functional behavior while improving structure

Addresses request to move branch detection logic from job-level 'if'
to trigger-level 'on' where possible within GitHub Actions limitations.

---------

Co-authored-by: Claude <noreply@anthropic.com>
Co-authored-by: Alexander Brown <drjkl@comfy.org>

.github/workflows/i18n.yaml

@@ -1,19 +1,17 @@
 name: Update Locales
 
 on:
+  # Manual dispatch for urgent translation updates  
+  workflow_dispatch:
+  # Only trigger on PRs to main/master - additional branch filtering in job condition
   pull_request:
-    branches: [ main, master, dev* ]
-    paths-ignore:
-      - '.github/**'
-      - '.husky/**'
-      - '.vscode/**'
-      - 'browser_tests/**'
-      - 'tests-ui/**'
+    branches: [ main ]
+    types: [opened, synchronize, reopened]
 
 jobs:
   update-locales:
-    # Don't run on fork PRs
-    if: github.event.pull_request.head.repo.full_name == github.repository
+    # Branch detection: Only run for manual dispatch or version-bump-* branches from main repo
+    if: github.event_name == 'workflow_dispatch' || (github.event.pull_request.head.repo.full_name == github.repository && startsWith(github.head_ref, 'version-bump-'))
     runs-on: ubuntu-latest
     steps:
     - uses: Comfy-Org/ComfyUI_frontend_setup_action@v3