Fix planner production server + use .ts extensions everywhere

- Fix createRequestHandler → createRequestListener (@react-router/node
  removed the old API)
- Move noEmit + allowImportingTsExtensions to tsconfig.base.json so all
  packages and apps inherit them consistently
- Add explicit .ts extensions to all remaining relative imports across
  packages and apps

Verified locally: node --experimental-strip-types server.ts starts and
responds 200.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

packages/gpx/src/parse.ts

@@ -1,5 +1,5 @@
 import type { Waypoint } from "@trails-cool/types";
-import type { GpxData, TrackPoint, ElevationProfile } from "./types";
+import type { GpxData, TrackPoint, ElevationProfile } from "./types.ts";
 
 /**
  * Parse a GPX XML string into structured data.