fix: improve geocoding specificity and increase distance threshold for repeater systems

geocode_max_km: 25 → 75 km. The node is a physical receiver, not the system boundary;
digital repeaters extend coverage well beyond 25km (North White Plains at 35.5km from
the Yorktown node is a legitimate Westchester County location).

Query now fully qualified: "High Street" → "High Street, Yorktown, New York".
Added _get_node_state() which reverse-geocodes the node position once (cached) using
Google Maps to get the state name, appended alongside the municipality.
Generic street names (High Street, Main Street) no longer resolve to wrong-country results.

drb-c2-core/app/config.py

@@ -32,7 +32,7 @@ class Settings(BaseSettings):
     embedding_no_location_threshold: float = 0.97 # slow-path: match without location (very high bar)
     embedding_cross_tg_threshold: float = 0.85    # cross-TG path: same dept + 2+ shared units
     location_proximity_km: float = 0.5        # radius for location-proximity matching
-    geocode_max_km: float = 25.0              # reject geocode results farther than this from the node
+    geocode_max_km: float = 75.0              # reject geocode results farther than this from the node
     incident_auto_resolve_minutes: int = 90   # auto-resolve after N minutes with no new calls
     recorrelation_scan_minutes: int = 60      # re-examine orphaned calls ended within this window
     tg_fast_path_idle_minutes: int = 90       # fast path: max minutes since incident last updated