feat: Add wardriving data import system and cleanup tools

Major Features:
- Multi-format GPS data import (Wigle CSV, GPS JSON, filename GPS)
- Data source tracking (test/mock/production)
- Database cleanup tools for managing test data
- JSON file persistence for simplified server
- UI improvements for map controls

Backend:
- Added wardriving_importer.py with WigleCSVImporter, GPSJSONImporter, BatchImporter
- Added data_source and session_id tracking to captures
- New API endpoints: DELETE /api/v1/admin/cleanup
- Auto-save/load functionality for captures_simple.json
- Updated stats endpoint to show data source breakdown

CLI Tools:
- scripts/import_wardriving_data.py - Batch import with --data-source flag
- scripts/cleanup_database.py - Clean by source, session, or all
- scripts/create_test_dataset.py - Generate GPS-tagged test data
- scripts/test_wardriving_import.py - Test suite for importers

Frontend:
- Fixed map controls z-index and positioning issues
- Moved controls to top-right to avoid zoom button overlap
- Fixed Leaflet zoom controls rendering over header
- Changed controls to position:fixed for persistent visibility
- Export map object to window.map for proper invalidateSize

Documentation:
- docs/WARDRIVING_IMPORT.md - Complete import guide
- docs/DATA_CLEANUP_GUIDE.md - Cleanup system documentation
- docs/TEST_LOCATIONS.md - Test GPS coordinates reference
- TEST_RESULTS_SUMMARY.md - Format testing results

Test Data:
- Created test_dataset_gps with 15 captures across 5 US cities
- All test data marked with data_source="test" for easy cleanup

Testing:
- Verified Wigle CSV import (1 capture from West LA)
- Verified GPS filename import (3 captures from UCLA area)
- Verified GPS JSON companion files (15 captures, 5 cities)
- Verified cleanup functionality (deleted 15 test captures)
- Verified data persistence across server restarts

🤖 Generated with Claude Code

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

static/css/main.css

@@ -108,16 +108,30 @@ main {
     height: 100%;
 }
 
+/* Leaflet zoom controls - move below header */
+.leaflet-top {
+    top: 90px !important;
+}
+
+/* Ensure Leaflet controls stay below header */
+.leaflet-control-zoom {
+    z-index: 500 !important;
+}
+
 .map-controls {
-    position: absolute;
-    top: 20px;
-    left: 20px;
+    position: fixed;
+    top: 90px;
+    right: 20px;
     background: white;
     padding: 1rem;
     border-radius: 0.5rem;
     box-shadow: var(--shadow-lg);
-    z-index: 1000;
+    z-index: 500;
     min-width: 300px;
+    max-width: 350px;
+    max-height: calc(100vh - 120px);
+    overflow-y: auto;
+    pointer-events: auto;
 }
 
 .control-group {
@@ -551,8 +565,16 @@ footer p {
     }
 
     .map-controls {
-        position: static;
-        margin: 1rem;
+        position: fixed;
+        top: 80px;
+        right: 10px;
+        left: 10px;
+        max-width: calc(100% - 20px);
+        min-width: auto;
+    }
+
+    .leaflet-top {
+        top: 10px !important;
     }
 
     #map-section {