Reduces `pkg/discovery` test suite runtime by ~75% (from ~17s to ~4s) by eliminating unnecessary network timeouts and reducing wait intervals.
- Refactor `discovery.Service` to use an injectable `http.Client`, allowing UPnP enrichment tests to use `httptest.Server` instead of waiting for 5s network timeouts.
- Make `DNSDiscovery` forward timeout configurable and reduce it from 2s to 100ms in unit tests.
- Decrease discovery and context timeouts in mDNS and Unified discovery tests to the minimum required for stable verification (typically 100-200ms).
Tobias Gesellchen