Add Google Takeout data import infrastructure

Implements Phase 1 & 2 of Google Takeout RAG integration:
- Database migrations for calendar_events, location_history, search_history
- DAO implementations with hybrid time + semantic search
- Parsers for .ics, JSON, and HTML Google Takeout formats
- Import utilities with batch insert optimization

Features:
- CalendarEventDao: Hybrid time-range + semantic search for events
- LocationHistoryDao: GPS proximity with Haversine distance calculation
- SearchHistoryDao: Semantic-first search (queries are embedding-rich)
- Batch inserts for performance (1M+ records in minutes vs hours)
- OpenTelemetry tracing for all database operations

Import utilities:
- import_calendar: Parse .ics with optional embedding generation
- import_location_history: High-volume GPS data with batch inserts
- import_search_history: Always generates embeddings for semantic search

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

src/files.rs

@@ -217,7 +217,12 @@ pub async fn list_photos<TagD: TagDao, FS: FileSystemAccess>(
                     if let (Some(photo_lat), Some(photo_lon)) =
                         (exif.gps_latitude, exif.gps_longitude)
                     {
-                        let distance = haversine_distance(lat, lon, photo_lat, photo_lon);
+                        let distance = haversine_distance(
+                            lat as f64,
+                            lon as f64,
+                            photo_lat as f64,
+                            photo_lon as f64,
+                        );
                         distance <= radius_km
                     } else {
                         false