Fix rail pathfinding (#2950)

## Description:

This PR resolves a crash related to rail pathfinding reported on
Discord.

```
git checkout c179249cdd
npm run dev:staging
Replay id: kEbHPSP3
```

## Please complete the following:

- [x] I have added screenshots for all UI updates
- [x] I process any text displayed to the user through translateText()
and I've added it to the en.json file
- [x] I have added relevant tests to the test directory
- [x] I confirm I have thoroughly tested these changes and take full
responsibility for any bugs introduced

## Please put your Discord username so you can be contacted if a bug or
regression is found:

moleole

Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>
Co-authored-by: Ryan <7389646+ryanbarlow97@users.noreply.github.com>

src/core/game/RailNetworkImpl.ts

@@ -23,7 +23,7 @@ export interface StationManager {
 export class StationManagerImpl implements StationManager {
   private stations: Set<TrainStation> = new Set();
   private stationsById: (TrainStation | undefined)[] = [];
-  private nextId = 0;
+  private nextId = 1; // Start from 1; 0 is reserved as invalid/sentinel
 
   addStation(station: TrainStation) {
     station.id = this.nextId++;

src/core/pathfinding/PathFinder.Station.ts

@@ -42,7 +42,7 @@ class StationGraphAdapter implements AStarAdapter {
   }
 
   maxNeighbors(): number {
-    return 8;
+    return 32;
   }
 
   maxPriority(): number {