feat: annotate game label adds with detection source in backfill logs

Each game label add now shows its source in the per-issue log line:
  #240: added "game: Opposing Force" (text-match)
  #248: added "game: Counter-Strike: Global Offensive" (form-field)
  #N:   added "game: X" (ai-fallback)

Non-game labels (engine, type, needs, etc.) are unchanged.

Author: dgibbs64

.github/workflows/labeler.yml

@@ -1293,6 +1293,7 @@ jobs:
 
                 // Games and engines
                 const desiredGames = new Set();
+                const gameLabelSource = new Map(); // label → 'form-field' | 'text-match' | 'ai-fallback'
                 const desiredServerScripts = new Set();
                 const gameField = extractSection(body, 'Game');
                 const gameCandidates = parseGameCandidates(gameField);
@@ -1301,15 +1302,21 @@ jobs:
                   const normalizedCandidate = normalizeName(candidate);
                   const mapped =
                     gameAliasToLabel.get(normalizedCandidate) || gameLabelByNormalized.get(normalizedCandidate);
-                  if (mapped) desiredGames.add(mapped);
+                  if (mapped) {
+                    desiredGames.add(mapped);
+                    gameLabelSource.set(mapped, 'form-field');
+                  }
                   const mappedScript = gameAliasToScript.get(normalizedCandidate);
                   if (mappedScript) desiredServerScripts.add(mappedScript);
                 }
 
                 // Legacy issues often have no form section; fall back to deterministic text matching.
                 if (desiredGames.size === 0) {
                   const fromText = findGamesFromText(`${title}\n${body}`, gameAliasToLabel, gameAliasToScript);
-                  for (const label of fromText.labels) desiredGames.add(label);
+                  for (const label of fromText.labels) {
+                    desiredGames.add(label);
+                    gameLabelSource.set(label, 'text-match');
+                  }
                   for (const scriptName of fromText.scripts) desiredServerScripts.add(scriptName);
                 }
 
@@ -1365,6 +1372,7 @@ jobs:
                           );
                           if (hasAliasEvidence) {
                             desiredGames.add(mappedLabel);
+                            gameLabelSource.set(mappedLabel, 'ai-fallback');
                             const mappedScript = gameAliasToScript.get(detectedGame);
                             if (mappedScript) desiredServerScripts.add(mappedScript);
                             aiGameMatches += 1;
@@ -1451,7 +1459,8 @@ jobs:
                       labels: [label],
                     });
                     labelAdded += 1;
-                    console.log(`#${rawIssue.number}: added "${label}"`);
+                    const gameSource = gameLabelSource.get(label);
+                    console.log(`#${rawIssue.number}: added "${label}"${gameSource ? ` (${gameSource})` : ''}`);
                   } catch (err) {
                     console.log(`#${rawIssue.number}: could not add "${label}": ${err.message}`);
                   }