feat: smart NFO management and correct episode date field mapping

💾 Smart NFO File Management:
- Add intelligent content comparison to prevent unnecessary file overwrites
- Only update NFO files when content actually changes (ignoring timestamp differences)
- Dramatically reduce file system writes and improve scan performance
- Applied to both TV episodes and movies for comprehensive efficiency
- New _nfo_content_matches() method for smart content comparison

🗓️ Fix Episode Date Field Mapping:
- BREAKING: Correct date field usage in episode NFOs
- <aired> and <premiered>: Now use historical air dates (e.g., 1951-10-15)
- <dateadded>: Correctly shows actual download/import date (e.g., 2025-09-13)
- Resolves confusion between when show aired vs when user downloaded it
- Media servers now show historically accurate metadata with working "Recently Added"

🎯 Technical Changes:
- Enhanced create_episode_nfo() with content comparison logic
- Enhanced create_movie_nfo() with content comparison logic
- Separated historical date logic from import date logic
- Added comprehensive debug logging for file skip/update decisions

🏆 User Experience:
- Faster scans with fewer unnecessary file operations
- Correct historical context in media servers
- "Recently Added" functionality preserved and working
- No more metadata confusion between air dates and import dates

Example NFO output:
- <aired>1951-10-15</aired> (historical)
- <dateadded>2025-09-13T21:39:28+00:00</dateadded> (when downloaded)
- <premiered>1951-10-15</premiered> (historical)

SUMMARY.md

@@ -167,6 +167,49 @@ Preserve movie and TV import dates in Emby/Jellyfin/Plex by preventing upgraded
 
 ---
 
+### 🆕 v0.6.3 NFO Management & Date Accuracy Improvements (September 2025)
+
+**💾 Smart NFO File Management:**
+- **Problem**: NFOguard was rewriting NFO files for every episode on every scan, even untouched ones
+- **Solution**: Intelligent content comparison - only updates NFOs when content actually changes
+- **Performance**: Dramatically reduces unnecessary file system writes and processing time
+- **Both Media Types**: Applied to both TV episodes and movies for comprehensive efficiency
+
+**🗓️ Correct Date Field Mapping:**
+- **Problem**: Episode NFOs showing import dates (2025) for historical fields `<aired>` and `<premiered>`
+- **Root Cause**: Logic incorrectly used `dateadded` for all date fields instead of proper separation
+- **Fix**: Clear separation of date meanings:
+  - `<aired>`: Historical air date (e.g., 1951-10-15 for I Love Lucy)
+  - `<premiered>`: Historical premiere date (same as aired)
+  - `<dateadded>`: Actual download/import date (e.g., 2025-09-13T21:39:28+00:00)
+
+**🎯 Technical Implementation:**
+- **New Method**: `_nfo_content_matches()` - smart content comparison ignoring timestamps
+- **Enhanced Logic**: Episodes now correctly separate historical vs import dates
+- **Skip Logic**: Files marked "already up-to-date" when no meaningful changes detected
+- **Logging**: Clear debug output showing when files are skipped vs updated
+
+**🏆 User Experience Improvements:**
+- **Correct Metadata**: Shows historically accurate air dates in media servers
+- **Recently Added**: Still works properly using `dateadded` field
+- **Performance**: Faster scans with fewer unnecessary file writes
+- **Accuracy**: No more confusion between when show aired vs when you downloaded it
+
+**📋 Example Before/After:**
+```xml
+<!-- Before (Wrong) -->
+<aired>2025-09-13</aired>           <!-- Import date in wrong field -->
+<dateadded>2025-09-13T21:39:28+00:00</dateadded>
+<premiered>2025-09-13</premiered>   <!-- Import date in wrong field -->
+
+<!-- After (Correct) -->
+<aired>1951-10-15</aired>           <!-- Historical air date ✅ -->
+<dateadded>2025-09-13T21:39:28+00:00</dateadded>  <!-- When downloaded ✅ -->
+<premiered>1951-10-15</premiered>   <!-- Historical premiere ✅ -->
+```
+
+---
+
 **Last Updated:** September 13, 2025  
-**Version:** v0.6.2-dev  
+**Version:** v0.6.3-dev  
 **Status:** Enhanced Production Ready