feat: Add 'update' command to NFO CLI tool

- New command: python -m src.cli.nfo_cli update
- Updates all existing NFO files with fresh TMDB data
- Optionally re-downloads media files
- Shows progress with success/error count
- Updates task3_status.md to mark update_tvshow_nfo() as complete

docs/task3_status.md

@@ -149,23 +149,16 @@ The unit tests were written based on assumptions about the API that don't match
 
 2. **Unit Test Refactoring** (2-3 hours, optional)
 
-    - Update test_image_downloader.py with dependency injection
-    - Fix test_nfo_generator.py validation tests
-    - Update test_tmdb_client.py mocking strategy
-    - Add test_nfo_service.py with comprehensive tests
+    - ✅ NFO XML parsing tests added (4 tests passing)
+    - ⚠️ TMDBClient tests need refactoring (async mocking challenges)
+    - ⚠️ ImageDownloader tests need dependency injection
     - Alternative: Replace with more integration tests
 
-3. **NFOService.update_tvshow_nfo()** (1 hour, optional)
-
-    - Currently raises NotImplementedError
-    - Parse existing NFO to extract TMDB ID
-    - Refetch from TMDB and regenerate
-    - Update media files
-
-4. **Error Recovery** (1 hour, optional)
+3. **Enhanced Error Recovery** (1 hour, optional)
     - Graceful handling if TMDB API fails during scan
-    - Don't block scan if NFO creation fails
+    - Retry queue for failed NFO creations
     - Enhanced logging for debugging
+    - Background job for bulk operations
 
 ### Future API Integration (Separate Tasks)
 
@@ -176,11 +169,13 @@ The unit tests were written based on assumptions about the API that don't match
 
 ## 🐛 Known Issues / Future Enhancements
 
-1. **NFOService.update_tvshow_nfo()** - Not implemented (optional)
+1. **NFOService.update_tvshow_nfo()** - ✅ **IMPLEMENTED**
 
-    - Currently raises `NotImplementedError`
-    - Would need to parse existing NFO to extract TMDB ID
-    - Then refetch and regenerate
+    - Parses existing NFO to extract TMDB ID from uniqueid or tmdbid elements
+    - Fetches fresh metadata from TMDB API
+    - Regenerates NFO with updated data
+    - Optionally re-downloads media files
+    - Comprehensive error handling for edge cases
 
 2. **Unit Tests** - Need refactoring (optional)
 
@@ -263,9 +258,9 @@ Task 3 is **95% Complete** and **Production Ready**.
 
 **Optional Future Work (Not blocking):**
 
--   Unit test refactoring (mocking strategy needs redesign)
--   update_tvshow_nfo() implementation
--   Advanced error recovery features
+-   Unit test refactoring (mocking strategy needs redesign for async code)
+-   ~~update_tvshow_nfo() implementation~~ ✅ **DONE**
+-   Advanced error recovery features (retry queue, background jobs)
 
 ## ⏱️ Time Investment Summary