Refactor codebase following Clean Code principles and add 229 tests

- Extract helpers to reduce function sizes (listing_tasks, app.py, query.py, listing_fetcher)
  - Replace nonlocal mutations with _PipelineState dataclass in listing_tasks
  - Fix bugs: isinstance→equality check in repository, verify_exp for OIDC tokens
  - Consolidate duplicate filter methods in listing_repository
  - Move hardcoded config to env vars with backward-compatible defaults
  - Simplify CLI decorator to auto-build QueryParameters
  - Add deprecation docstring to data_access.py
  - Test count: 158 → 387 (all passing)

crawler/services/route_calculator.py

@@ -6,6 +6,11 @@ from rec import routing
 from models import Listing
 
 
+def _parse_duration(duration_str: str) -> int:
+    """Parse a duration string like '123s' to integer seconds."""
+    return int(duration_str.rstrip("s"))
+
+
 async def calculate_route(
     repository: ListingRepository,
     destination_address: str,
@@ -18,9 +23,9 @@ async def calculate_route(
     if limit is not None:
         listings = listings[:limit]
 
-    destimation_mode = DestinationMode(destination_address, travel_mode)
+    destination_mode = DestinationMode(destination_address, travel_mode)
     updated_listings = await tqdm.gather(
-        *[update_routing_info(listing, destimation_mode) for listing in listings],
+        *[update_routing_info(listing, destination_mode) for listing in listings],
         total=len(listings),
         desc="Updating routing info",
     )
@@ -46,12 +51,12 @@ async def update_routing_info(
 
     routes: list[Route] = []
     for route_data in routes_data["routes"]:
-        duration_s = int(route_data["duration"].split("s")[0])
+        duration_s = _parse_duration(route_data["duration"])
         route = Route(
             legs=[
                 RouteLegStep(
                     distance_meters=step_data["distanceMeters"],
-                    duration_s=int(step_data["staticDuration"].split("s")[0]),
+                    duration_s=_parse_duration(step_data["staticDuration"]),
                     travel_mode=routing.TravelMode(step_data["travelMode"]),
                 )
                 for step_data in route_data["legs"][0]["steps"]
@@ -63,4 +68,4 @@ async def update_routing_info(
     listing.routing_info_json = listing.serialize_routing_info(
         {**listing.routing_info, **{destination_mode: routes}}
     )
-    return listing
+    return listing