fix(client): POI category key mismatch — use poi_category from wire format

protocol.gd decoded server's poi_category as "category", minimap.gd
read "category" — both now use "poi_category" matching the wire format.
Protocol falls back to "category" for older server snapshots.

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

client/scripts/protocol/protocol.gd

@@ -207,7 +207,7 @@ static func decode_snapshot(bytes: PackedByteArray) -> Variant:
 				})
 
 	# v14: poi_list (#151) — discovered POIs for minimap rendering.
-	# Each entry: {poi_id, name, x, y, z, category}. Positions in sim tile coords.
+	# Each entry: {poi_id, name, x, y, z, poi_category}. Positions in sim tile coords.
 	var poi_list: Array = []
 	var raw_pois: Variant = raw.get("poi_list")
 	if raw_pois is Array:
@@ -219,7 +219,7 @@ static func decode_snapshot(bytes: PackedByteArray) -> Variant:
 					"x": int(raw_poi["x"]),
 					"y": int(raw_poi["y"]),
 					"z": int(raw_poi.get("z", 0)),
-					"category": str(raw_poi.get("category", "Location")),
+					"poi_category": str(raw_poi.get("poi_category", raw_poi.get("category", "Location"))),
 				})
 
 	# v14: examine_result (#174, #242) — character-filtered observation text.