0.52.1

## What's Changed
* Misc small HTML Validation fixes by @dgtlmoon in https://github.com/dgtlmoon/changedetection.io/pull/3704
* Use soft delays instead of blocking time sleeps by @dgtlmoon in https://github.com/dgtlmoon/changedetection.io/pull/3710
     Multi-language / Translations Support (#3696)
      - Complete internationalization system implemented
      - Support for 7 languages: Czech (cs), German (de), French (fr), Italian (it), Korean (ko), Chinese Simplified (zh), Chinese Traditional (zh_TW)
      - Language selector with localized flags and theming
      - Flash message translations
      - Multiple translation fixes and improvements across all languages
      - Language setting preserved across redirects
    
      Pluggable Content Fetchers (#3653)
      - New architecture for extensible content fetcher system
      - Allows custom fetcher implementations
    
      Image / Screenshot Comparison Processor (#3680)
      - New processor for visual change detection (disabled for this release)
      - Supporting CSS/JS infrastructure added
    
      UI Improvements
    
      Design & Layout
      - Auto-generated tag color schemes
      - Simplified login form styling
      - Removed hard-coded CSS, moved to SCSS variables
      - Tag UI cleanup and improvements
      - Automatic tab wrapper functionality
      - Menu refactoring for better organization
      - Cleanup of offset settings
      - Hide sticky tabs on narrow viewports
      - Improved responsive layout (#3702)
    
      User Experience
      - Modal alerts/confirmations on delete/clear operations (#3693, #3598, #3382)
      - Auto-add https:// to URLs in quickwatch form if not present
      - Better redirect handling on login (#3699)
      - 'Recheck all' now returns to correct group/tag (#3673)
      - Language set redirect keeps hash fragment
      - More friendly human-readable text throughout UI
    
      Performance & Reliability
    
      Scheduler & Processing
      - Soft delays instead of blocking time.sleep() calls (#3710)
      - More resilient handling of same UUID being processed (#3700)
      - Better Puppeteer timeout handling
      - Improved Puppeteer shutdown/cleanup (#3692)
      - Requests cleanup now properly async
    
      History & Rendering
      - Faster server-side "difference" rendering on History page (#3442)
      - Show ignored/triggered rows in history
      - API: Retry watch data if watch dict changed (more reliable)
    
      API Improvements
    
      - Watch get endpoint: retry mechanism for changed watch data
      - WatchHistoryDiff API endpoint includes extra format args (#3703)
    
      Testing Improvements
    
      - Replace time.sleep with wait_for_notification_endpoint_output (#3716)
      - Test for mode switching (#3701)
      - Test for #3720 added (#3725)
      - Extract-text difference test fixes
      - Improved dev workflow
    
      Bug Fixes
    
      - Notification error text output (#3672, #3669, #3280)
      - HTML validation fixes (#3704)
      - Template discovery path fixes
      - Notification debug log now uses system locale for dates/times
      - Puppeteer spelling mistake in log output
      - Recalculation on anchor change
      - Queue bubble update disabled temporarily
    
    
      Dependency Updates
    
      - beautifulsoup4 updated (#3724)
      - psutil 7.1.0 → 7.2.1 (#3723)
      - python-engineio ~=4.12.3 → ~=4.13.0 (#3707)
      - python-socketio ~=5.14.3 → ~=5.16.0 (#3706)
      - flask-socketio ~=5.5.1 → ~=5.6.0 (#3691)
      - brotli ~=1.1 → ~=1.2 (#3687)
      - lxml updated (#3590)
      - pytest ~=7.2 → ~=9.0 (#3676)
      - jsonschema ~=4.0 → ~=4.25 (#3618)
      - pluggy ~=1.5 → ~=1.6 (#3616)
      - cryptography 44.0.1 → 46.0.3 (security) (#3589)
    
      Documentation
    
      - README updated with viewport size setup information
    
      Development Infrastructure
    
      - Dev container only built on dev branch
      - Improved dev workflow tooling




**Full Changelog**: https://github.com/dgtlmoon/changedetection.io/compare/0.51.4...0.52.1