fix(cache): back the response cache with Redis on cache-manager v7

[anderdc]

Summary

The response cache module was copied from das-gittensor, which runs @nestjs/cache-manager v2 / cache-manager v5. das-github-mirror is on v3 / cache-manager v7 (Keyv-based), where the config shape changed — so the copied config was silently broken on arrival (commit b771271):

• v3 reads the store list from stores (plural, Keyv instances). The singular store key was ignored, so Redis was never used.
• v3 reads the entry TTL from the top-level ttl. The ttl nested inside redisStore({ ttl }) never reached the cache.

Net effect in production: an in-memory cache with no expiry. Cached GET responses were pinned from process start and served stale until the next restart — observed ~20h stale on /api/v1/miners/:id/issues.

This PR:

• Replaces cache-manager-redis-yet (v5-era, incompatible with cache-manager v7) with @keyv/redis, the Keyv-era Redis adapter.
• Passes stores: [Keyv] + top-level ttl — the shape v3 actually reads.
• Namespaces cache keys apicache to stay clear of BullMQ's bull:* keyspace on the shared Redis instance.
• Adds an error listener so a Redis outage degrades to an uncached request instead of crashing the process on an unhandled EventEmitter error.
• Types the factory return as CacheModuleOptions instead of any — the type hole that let the wrong shape compile silently.

Related Issues

None.

Type of Change

• Bug fix

Testing

• npm run build — passes
• npx eslint / prettier --check — clean
• Compiled output confirms the @keyv/redis wiring (stores: [Keyv], apicache namespace)
• Runtime TTL/Redis behavior verifies on deploy (the deploy also clears the current broken in-memory cache)

Checklist

• I have read the Contributing Guide
• Code builds without errors
• New and existing tests pass (if applicable) — no cache tests exist in the repo
• Documentation updated (if applicable) — n/a
• No unnecessary dependencies added — net swap: −cache-manager-redis-yet, +@keyv/redis (the correct adapter for the installed cache-manager version)

Note

This fixes the application cache only. A reverse-proxy cache fronting mirror.gittensor.io (the x-cache response header) is a separate layer outside this repo and should be checked independently.