Implement labeler HTTP stage and wire into pipeline
Add the HTTP stage (com.atproto.label.queryLabels) with the RawHttpTee
trait, RealHttpTee reqwest implementation, HttpStageError + typed
HttpDecodeFailure miette diagnostic with precise JSON error spans, and
six check-result IDs covering AC3.1-AC3.6. Thread a shared
reqwest::Client through LabelerOptions so identity and HTTP stages
reuse one TLS stack, and inject a RawHttpTee through LabelerOptions so
tests can substitute a fake. Update the 12 Phase 3 identity tests to
inject a FakeRawHttpTee returning a healthy one-label response and
refresh the identity snapshots accordingly.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>