fix(complement-race): reduce initial momentum from 50 to 10 to prevent train sailing past first station

The train was starting with too much momentum (50), causing it to sail past the first station without requiring user input. Reduced to 10 for a gentle push that still requires player engagement.

Changes:
- Reduce initial momentum from 50 to 10 in all three locations:
  - Initial state (useState)
  - Game start initialization
  - Route reset when advancing to next route
- Update pressure calculation to match new starting momentum

With momentum=10: speed = 1.5% per second (gentle start requiring answers to progress)
vs momentum=50: speed = 7.5% per second (too aggressive, reaches station without input)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

apps/web/src/arcade-games/complement-race/Provider.tsx

@@ -254,7 +254,7 @@ export function ComplementRaceProvider({ children }: { children: ReactNode }) {
   const lastLogRef = useState({ key: '', count: 0 })[0]
 
   // Client-side game state (NOT synced to server - purely visual/gameplay)
-  const [clientMomentum, setClientMomentum] = useState(50) // Start at 50
+  const [clientMomentum, setClientMomentum] = useState(10) // Start at 10 for gentle push
   const [clientPosition, setClientPosition] = useState(0)
   const [clientPressure, setClientPressure] = useState(0)
   const lastUpdateRef = useRef(Date.now())
@@ -373,9 +373,9 @@ export function ComplementRaceProvider({ children }: { children: ReactNode }) {
         gameStartTimeRef.current = Date.now()
         lastUpdateRef.current = Date.now()
         // Reset client state for new game
-        setClientMomentum(50)
+        setClientMomentum(10) // Start with gentle push
         setClientPosition(0)
-        setClientPressure((50 / 100) * 150) // Initial pressure from starting momentum
+        setClientPressure((10 / 100) * 150) // Initial pressure from starting momentum
       }
     } else {
       // Reset when game ends
@@ -435,7 +435,7 @@ export function ComplementRaceProvider({ children }: { children: ReactNode }) {
     // When route changes, reset position and give starting momentum
     if (currentRoute > 1 && compatibleState.style === 'sprint') {
       setClientPosition(0)
-      setClientMomentum(50) // Reset to starting momentum
+      setClientMomentum(10) // Reset to starting momentum (gentle push)
     }
   }, [multiplayerState.currentRoute, compatibleState.style])