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/bin/migrate_exif.rs

@@ -102,11 +102,11 @@ fn main() -> anyhow::Result<()> {
                         width: exif_data.width,
                         height: exif_data.height,
                         orientation: exif_data.orientation,
-                        gps_latitude: exif_data.gps_latitude,
-                        gps_longitude: exif_data.gps_longitude,
-                        gps_altitude: exif_data.gps_altitude,
-                        focal_length: exif_data.focal_length,
-                        aperture: exif_data.aperture,
+                        gps_latitude: exif_data.gps_latitude.map(|v| v as f32),
+                        gps_longitude: exif_data.gps_longitude.map(|v| v as f32),
+                        gps_altitude: exif_data.gps_altitude.map(|v| v as f32),
+                        focal_length: exif_data.focal_length.map(|v| v as f32),
+                        aperture: exif_data.aperture.map(|v| v as f32),
                         shutter_speed: exif_data.shutter_speed,
                         iso: exif_data.iso,
                         date_taken: exif_data.date_taken,