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>

src/locales/CONTRIBUTING.md

@@ -84,8 +84,9 @@ pnpm locale
 
 #### Option B: Let CI Handle It (Recommended)
 - Create your PR with the configuration changes above
-- Our GitHub CI will automatically generate translation files
-- Empty JSON files are fine - they'll be populated by the workflow
+- **Important**: Translation files will be generated during release PRs, not feature PRs
+- Empty JSON files are fine - they'll be populated during the next release workflow
+- For urgent translation needs, maintainers can manually trigger the workflow
 
 ### Step 3: Test Your Changes
 
@@ -110,11 +111,23 @@ pnpm dev        # Start development server
 
 ## What Happens in CI
 
-Our automated translation workflow:
+Our automated translation workflow now runs on release PRs (version-bump-* branches) to improve development performance:
+
+### For Feature PRs (Regular Development)
+- **No automatic translations** - faster reviews and fewer conflicts
+- **English-only development** - new strings show in English until release
+- **Focus on functionality** - reviewers see only your actual changes
+
+### For Release PRs (version-bump-* branches)
 1. **Collects strings**: Scans the UI for translatable text
-2. **Updates English files**: Ensures all strings are captured
+2. **Updates English files**: Ensures all strings are captured  
 3. **Generates translations**: Uses OpenAI API to translate to all configured languages
-4. **Commits back**: Automatically updates your PR with complete translations
+4. **Commits back**: Automatically updates the release PR with complete translations
+
+### Manual Translation Updates
+If urgent translation updates are needed outside of releases, maintainers can:
+- Trigger the "Update Locales" workflow manually from GitHub Actions
+- The workflow supports manual dispatch for emergency translation updates
 
 ## File Structure