refactor: replace console.log/error with structured logger across server

Migrate all server modules to use the centralized logger (lib/logger.ts)
instead of raw console calls. Lint warnings reduced from 74 to 25.
Remaining warnings are only no-floating-promises in game engine code.

Files updated: orchestrator.ts, ranked-queue.ts, human-responses.ts,
payments.ts, fight-loop.ts, app.ts, routes/payments.ts
Files suppressed: logger.ts, fight-loop-cli.ts, migrate.ts (legitimate console use)

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

server/src/db/migrate.ts

@@ -82,5 +82,6 @@ for (const sql of migrations) {
   try { sqlite.exec(sql) } catch { /* column already exists */ }
 }
 
+// eslint-disable-next-line no-console -- migration script runs before logger init
 console.log('[botfights] database migrated')
 sqlite.close()