docs(phase-03): evolve PROJECT.md after phase completion

.planning/PROJECT.md

@@ -19,7 +19,12 @@ Network traffic patterns are instantly recognizable as distinct sounds — a pin
 
 ### Active
 
-- [ ] Auto-cluster unrecognized traffic patterns and assign them unique tones
+(None — all requirements validated through Phase 3)
+
+### Validated in Phase 3
+
+- [x] Auto-cluster unrecognized traffic patterns and assign them unique tones — Validated in Phase 3 (hash-bucketed into 4 unknown classes with distinct dissonant tones)
+- [x] End-to-end pipeline: capture → classify → synthesize → MP3 output — Validated in Phase 3
 
 ### Validated in Phase 2