fix: clarify scoring system in track placement and guessing logic

src/server-deno/application/GameService.ts

@@ -224,6 +224,15 @@ export class GameService {
 
   /**
    * Check title and artist guess
+   * 
+   * SCORING SYSTEM:
+   * - Tokens: Awarded ONLY for correctly guessing BOTH title AND artist
+   *   - 1 token per round (can only get once per track)
+   *   - Used as currency/bonus points
+   * 
+   * - Score: Number of correctly placed tracks in timeline (timeline.length)
+   *   - Increases only when placement is correct
+   *   - This is the main win condition
    */
   async checkTitleArtistGuess(
     room: RoomModel,
@@ -274,6 +283,11 @@ export class GameService {
 
   /**
    * Place track in timeline
+   * 
+   * SCORING SYSTEM:
+   * - Correct placement: Adds track to timeline, increasing score (timeline.length)
+   * - Incorrect placement: Track is discarded, no score increase
+   * - NO tokens awarded here - tokens are only from title+artist guesses
    */
   async placeInTimeline(
     room: RoomModel,
@@ -318,7 +332,7 @@ export class GameService {
       logger.warn(`Track has no year: ${track.title}`);
     }
 
-    // Update timeline if correct
+    // Update timeline if correct (score is the timeline length)
     if (correct) {
       const newTimeline = [...timeline];
       newTimeline.splice(slot, 0, {
@@ -328,19 +342,18 @@ export class GameService {
         artist: track.artist,
       });
       room.state.timeline[playerId] = newTimeline;
-
-      // Award 1 token for correct placement (independent of title+artist token)
-      room.state.tokens[playerId] = (room.state.tokens[playerId] || 0) + 1;
       
+      // Score increases automatically (it's the timeline length)
+      // NO token awarded here - tokens are only from title+artist guesses
       logger.info(
-        `Player ${playerId} correctly placed track in timeline. Awarded 1 token for placement.`
+        `Player ${playerId} correctly placed track in timeline. Score is now ${newTimeline.length}.`
       );
     } else {
       // Discard the track
       room.discard.push(track);
       
       logger.info(
-        `Player ${playerId} incorrectly placed track. No token awarded.`
+        `Player ${playerId} incorrectly placed track. No score increase.`
       );
     }