Keep all burst images, use last timestamp as passage time

- passage_images table stores every image in a burst sequence
- Passage timestamp = last image (chronologically) in the burst
- Review UI: image slider to browse all burst images, slider ends
  at the official passage time (rightmost = last image)
- API: GET /api/passages/{id}/images

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/profile_db.py

@@ -33,7 +33,6 @@ async def init_db(db: aiosqlite.Connection) -> None:
             gps_lon         REAL,
             gps_alt         REAL,
             confidence      REAL,
-            proximity_score REAL NOT NULL DEFAULT 0,
             id_method       TEXT,
             source_image    TEXT,
             needs_review    INTEGER NOT NULL DEFAULT 0,
@@ -41,9 +40,19 @@ async def init_db(db: aiosqlite.Connection) -> None:
             created_at      TEXT NOT NULL DEFAULT (datetime('now'))
         );
 
+        CREATE TABLE IF NOT EXISTS passage_images (
+            image_id        TEXT PRIMARY KEY,
+            passage_id      TEXT NOT NULL REFERENCES passages(passage_id) ON DELETE CASCADE,
+            image_path      TEXT NOT NULL,
+            timestamp_utc   TEXT NOT NULL,
+            proximity_score REAL NOT NULL DEFAULT 0,
+            created_at      TEXT NOT NULL DEFAULT (datetime('now'))
+        );
+
         CREATE INDEX IF NOT EXISTS idx_passages_profile ON passages(profile_id);
         CREATE INDEX IF NOT EXISTS idx_passages_station ON passages(station);
         CREATE INDEX IF NOT EXISTS idx_passages_needs_review ON passages(needs_review);
+        CREATE INDEX IF NOT EXISTS idx_passage_images_passage ON passage_images(passage_id);
     """)
     await db.commit()