feat(redis): connect to Redis at startup with shared client

[diangogav]

What

Connect to Redis during the boot sequence and log successful connections to both Postgres datasources and Redis.

Why

Bun's `RedisClient` connects lazily — on the first command. Before this change the Redis client was instantiated inside `ticket-router.ts` but never connected at startup, so a misconfigured or down Redis would only surface on the first `POST /game-tickets` request, not at boot.

Changes

• `src/shared/redis/redisClient.ts` (new): extract the Redis client to a shared module-level singleton, consistent with how the Postgres datasources are wired. This ensures the startup check validates the same connection the ticket repository uses.
• `src/index.ts`: `await redisClient.connect()` in the boot sequence, following the existing Postgres pattern. Success logs added for both Postgres schemas and Redis via `.then()` (so the "Connected" log only prints on actual success, not when `.catch` swallows an error).
• `src/server/routes/ticket-router.ts`: reuse the shared client instead of creating its own.

Notes

Keeps the existing log-and-continue error semantics (matches Postgres): a connection failure is logged but does not abort the process. This is detection-early, not strict fail-fast, intentionally consistent with the rest of the boot.