refactor: eliminate any types across server and TTS worker

- app.ts: type serveFile context parameter as Hono Context
- bets.ts: replace catch(err: any) with err: unknown + narrowing
- fight-loop.ts: type pickMatchup style as union literal, replace
  as any casts with proper result type
- tts-worker.ts: import KokoroTTS type, use ProgressInfo inference

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

server/src/engine/fight-loop.ts

@@ -78,8 +78,8 @@ export async function startFightLoop(options: FightLoopOptions = {}): Promise<vo
             onRoundComplete({
               round: event.data.round as number,
               hp: event.data.hp as { a: number; b: number },
-              challengeType: (event.data.result as any)?.challengeType || '',
-              winnerId: (event.data.result as any)?.winnerId || null,
+              challengeType: (event.data.result as { challengeType?: string } | undefined)?.challengeType || '',
+              winnerId: (event.data.result as { winnerId?: string | null } | undefined)?.winnerId || null,
             })
           }
         })
@@ -151,7 +151,7 @@ export async function startFightLoop(options: FightLoopOptions = {}): Promise<vo
 
 function pickMatchup(
   bots: { id: string; eloRating: number; name: string; wins: number; losses: number }[],
-  style: string,
+  style: 'elo_close' | 'random' | 'mixed',
   fightNum: number,
 ): [typeof bots[0], typeof bots[0]] {
   const sorted = [...bots].sort((a, b) => b.eloRating - a.eloRating)