Remove daemon storage cache (bd-33, bd-34, bd-35)

- Deleted server_cache_storage.go (~300 lines)
- Removed cache fields from Server struct
- Simplified database routing to use s.storage directly
- Removed cache metrics from health and metrics endpoints
- Deleted server_eviction_test.go (cache eviction tests)
- Cleaned up limits_test.go (removed cache assertions)
- All tests passing

internal/rpc/client.go

@@ -74,8 +74,8 @@ func TryConnectWithTimeout(socketPath string, dialTimeout time.Duration) (*Clien
 	}
 
 	if os.Getenv("BD_DEBUG") != "" {
-		fmt.Fprintf(os.Stderr, "Debug: connected to daemon (status: %s, uptime: %.1fs, cache: %d)\n",
-			health.Status, health.Uptime, health.CacheSize)
+		fmt.Fprintf(os.Stderr, "Debug: connected to daemon (status: %s, uptime: %.1fs)\n",
+			health.Status, health.Uptime)
 	}
 
 	return client, nil