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

.planning/PROJECT.md

@@ -12,7 +12,14 @@ Being able to load a song, build a synchronized light show, and play it back liv
 
 ### Validated
 
-(None yet — ship to validate)
+**Communication (Phase 03)**
+- [x] UDP packet sender — animation + params format — implemented via `lightsync/protocol/animation_cmd.py` + `UDPSender`
+- [x] UDP frame sender — per-frame RGB pixel data — DRGB/DRGBW/DNRGB encoders in `lightsync/protocol/drgb.py`
+- [x] Device registry uses SK6812 and WS2801 abstraction with `encode_animation_cmd` — validated in Phase 01/03
+
+**Animations (Phase 03)**
+- [x] 7 built-in animation types (solid, chase, pulse, rainbow, strobe, color-wipe, fire) as pure renderers — `lightsync/animations/`
+- [x] Animation factory and registry — `create_animation()` by name, extensible for Phase 4+
 
 ### Active
 
@@ -94,4 +101,4 @@ This document evolves at phase transitions and milestone boundaries.
 4. Update Context with current state
 
 ---
-*Last updated: 2026-04-05 after initialization*
+*Last updated: 2026-04-06 — Phase 03 complete: communication protocol layer, animation library, E2E UDP validation*