cleanup: remove /api/landclass handler + lib/landclass.py (extraction #4 shadow)

/api/landclass is edge-shadowed since extraction #4 — navi-landclass :8424
serves the route via nginx. Cleanup #4 removed the last in-process consumer
(netsyms_api._reverse_landclass), so lib/landclass.py is now fully orphaned.

- api.py: drop the @app.route('/api/landclass') handler + the
  `from .landclass import lookup_landclass, format_summary` import.
- DELETE lib/landclass.py (only consumer was the deleted handler).
- DELETE lib/landclass_test.py (SUT gone).

PADUS_DB_* vars in /opt/recon/.env are now dead in recon — flagged for an
out-of-band post-merge cleanup, not touched here (data, not code).

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

lib/api.py

@@ -25,7 +25,6 @@ from werkzeug.utils import secure_filename
 from .utils import get_config, content_hash, clean_filename_to_title, derive_source_and_category, generate_download_url, setup_logging
 from .status import StatusDB
 from .deployment_config import get_deployment_config
-from .landclass import lookup_landclass, format_summary
 
 logger = setup_logging('recon.api')
 
@@ -1170,38 +1169,6 @@ def api_knowledge_stats():
     return jsonify(_cache['knowledge_stats'])
 
 
-@app.route('/api/landclass')
-def api_landclass():
-    """PAD-US land classification lookup for a point."""
-    config = get_deployment_config()
-    if not config.get('features', {}).get('has_landclass'):
-        return jsonify({'error': 'Land classification not available'}), 404
-
-    try:
-        lat = float(request.args.get('lat', ''))
-        lon = float(request.args.get('lon', ''))
-    except (ValueError, TypeError):
-        return jsonify({'error': 'lat and lon required as numbers'}), 400
-
-    if not (-90 <= lat <= 90) or not (-180 <= lon <= 180):
-        return jsonify({'error': 'lat must be -90..90, lon must be -180..180'}), 400
-
-    classifications = lookup_landclass(lat, lon)
-    is_public = len(classifications) > 0
-    is_private = len(classifications) == 0
-    summary = format_summary(classifications)
-
-    return jsonify({
-        'lat': lat,
-        'lon': lon,
-        'classifications': classifications,
-        'count': len(classifications),
-        'is_public': is_public,
-        'is_private': is_private,
-        'summary': summary,
-    })
-
-
 @app.route('/api/health')
 def api_health():
     """Health check endpoint for monitoring."""