CRITICAL: Fix database upsert bug preventing manual scan date persistence

**Root Cause**: upsert_movie_dates() was UPDATE-only, not proper upsert
- Manual scans failed to save dateadded to database (NULL values)
- Webhooks found database entries but with NULL dateadded
- Fell back to current timestamp instead of using proper import dates

**Database Fix**:
- Changed core/database.py upsert_movie_dates() from UPDATE to INSERT OR REPLACE
- Now properly saves dateadded during manual scans
- Preserves existing path with COALESCE fallback

**Webhook Enhancement**:
- Added comprehensive debug logging for database lookups
- Enhanced webhook date decision logic with proper fallback chain
- Only uses current timestamp as absolute last resort

**Impact**:
- Movies: Manual scans now persist dates, webhooks find existing entries ✅
- TV Shows: Not affected - already using proper INSERT OR REPLACE ✅
- Version: 1.5.5

nfoguard.py

@@ -970,26 +970,30 @@ class MovieProcessor:
         
         # Get existing dates
         existing = self.db.get_movie_dates(imdb_id)
+        _log("DEBUG", f"Database lookup for {imdb_id}: {existing}")
         
-        # Handle webhook mode - prioritize database, then use current timestamp
+        # Handle webhook mode - prioritize database, then use proper date logic
         if webhook_mode:
+            _log("DEBUG", f"Webhook mode: existing={bool(existing)}, has_dateadded={bool(existing and existing.get('dateadded')) if existing else 'N/A'}")
             if existing and existing.get("dateadded"):
                 _log("INFO", f"Webhook processing - using existing database entry: {existing['dateadded']} (source: {existing.get('source', 'unknown')})")
                 dateadded, source, released = existing["dateadded"], existing["source"], existing.get("released")
             else:
-                # Use current timestamp as source of truth for webhooks
-                local_tz = _get_local_timezone()
-                current_time = datetime.now(local_tz).isoformat(timespec="seconds")
-                _log("INFO", f"Webhook processing - using current timestamp as source of truth: {current_time}")
+                if existing:
+                    _log("INFO", f"Webhook processing - database entry exists but no dateadded field: {existing}")
+                else:
+                    _log("INFO", f"Webhook processing - no database entry found for {imdb_id}")
+                _log("INFO", f"Using full date decision logic")
+                # Use same logic as manual scan to check Radarr import dates, release dates, etc.
+                should_query = True  # Always query for webhooks when no database entry exists
+                dateadded, source, released = self._decide_movie_dates(imdb_id, movie_path, should_query, existing)
                 
-                # Still get release date for reference
-                released = None
-                if config.movie_poll_mode != "never":
-                    radarr_movie = self.radarr.movie_by_imdb(imdb_id) if self.radarr.api_key else None
-                    if radarr_movie:
-                        released = self._parse_date_to_iso(radarr_movie.get("inCinemas"))
-                
-                dateadded, source = current_time, "webhook:first_seen"
+                # Only if ALL date sources fail, fall back to current timestamp
+                if dateadded is None:
+                    local_tz = _get_local_timezone()
+                    current_time = datetime.now(local_tz).isoformat(timespec="seconds")
+                    _log("INFO", f"Webhook processing - all date sources failed, using current timestamp as last resort: {current_time}")
+                    dateadded, source = current_time, "webhook:fallback_timestamp"
         else:
             # Manual scan mode - determine if we should query APIs
             should_query = (