feat(relay): add early startup lifecycle logs

TESTING.md

@@ -358,7 +358,7 @@ CLI-side, only two matter for testing:
 | Symptom | Cause | Fix |
 |---------|-------|-----|
 | `relay error 500` or `400: restricted: not a channel member` after a code change | Stale binary | Rebuild and re-export `PATH`; or `cargo run` directly |
-| `Address already in use` on relay start (os error 48 on macOS, 98 on Linux) | Another relay (or stale process) holding `:3000` / `:8080` / `:9102` (or your override ports) | The panic line names the failing port — read it first. Then `lsof -iTCP:3000,8080,9102 -sTCP:LISTEN` (or your override equivalents). Kill the offender (`pkill -f buzz-relay`) or use the port-override block in step 3. If you already overrode and *still* collide, a prior reviewer left a relay running on the same alt ports — kill it or pick fresh ports |
+| `Address already in use` on relay start (os error 48 on macOS, 98 on Linux) | Another relay (or stale process) holding `:3000` / `:8080` / `:9102` (or your override ports) | Metrics-listener failures emit a `metrics_bind` lifecycle terminal with reason `bind`. Check the configured ports with `lsof -iTCP:3000,8080,9102 -sTCP:LISTEN` (or your override equivalents). Kill the offender (`pkill -f buzz-relay`) or use the port-override block in step 3. If you already overrode and *still* collide, a prior reviewer left a relay running on the same alt ports — kill it or pick fresh ports |
 | `auth_error: BUZZ_PRIVATE_KEY is required` | Env not exported into the CLI's shell | `export BUZZ_PRIVATE_KEY=...` (or pass `--private-key`) |
 | `auth_error: BUZZ_AUTH_TAG verification failed … signature verification failed` | A stale `BUZZ_AUTH_TAG` inherited from a parent shell. The local dev relay rejects it. | `unset BUZZ_AUTH_TAG` (see the scrub block in step 1) |
 | `auth-required: verification failed` on a closed relay | NIP-OA attestation needed | Set `BUZZ_AUTH_TAG` to the owner-issued JSON, or relax `BUZZ_REQUIRE_RELAY_MEMBERSHIP` |

crates/buzz-relay/src/lib.rs

@@ -25,6 +25,8 @@ pub mod error;
 pub mod handlers;
 /// Stateless HMAC-signed relay invite tokens (mint/verify).
 pub mod invite_token;
+/// Fixed-schema evidence for the relay's earliest startup steps.
+pub mod lifecycle;
 /// Inter-relay mesh startup wiring (`BUZZ_MESH` seam).
 pub mod mesh_boot;
 /// Prometheus metrics: recorder, upkeep, HTTP middleware.