feat(05-01): add per-connection show state and load handler to ws.py

- Import encode_animation_cmd and ShowModel at module level
- Add show, fired_ids, is_playing per-connection state variables
- Extend load handler to load show from show_store by show_id (D-04)
- play handler sets is_playing=True
- pause handler sets is_playing=False without touching fired_ids
- seek handler rebuilds fired_ids from show cues before seek position (D-03)

lightsync/api/ws.py

@@ -1,16 +1,19 @@
 """WebSocket hub — browser-driven tick/beat protocol (Phase 02-03 redesign).
 
 Browser sends position ticks at ~10Hz; server looks up the next beat and
-sends a beat notification back when one is near.
+sends a beat notification back when one is near. Phase 5 adds cue scheduling:
+the tick handler fires UDP animation commands at correct timestamps.
 
 Protocol (browser → server):
     {"type": "tick",  "position": 42.3}          — audio playback position
-    {"type": "play"}                               — playback started (log only for now)
-    {"type": "pause"}                              — playback paused (log only for now)
-    {"type": "seek",  "position": 42.3}           — seek event (log only for now)
+    {"type": "play",  "position": 42.3}           — playback started
+    {"type": "pause", "position": 42.3}           — playback paused
+    {"type": "seek",  "position": 42.3}           — seek event
+    {"type": "load",  "path": "...", "show_id": "uuid"}  — file + show loaded
 
 Protocol (server → browser):
     {"type": "beat",           "position": 42.3, "tempo": 120.0}  — beat detected near position
+    {"type": "preview_update", "device_id": "uuid", "animation": "...", "color": [...]}
     {"type": "error",          "message": "..."}                   — error response
 """
 from __future__ import annotations
@@ -19,6 +22,8 @@ import bisect
 import json
 import logging
 from fastapi import APIRouter, WebSocket, WebSocketDisconnect
+from lightsync.protocol.animation_cmd import encode_animation_cmd
+from lightsync.models.show import ShowModel
 
 logger = logging.getLogger(__name__)
 
@@ -81,6 +86,11 @@ async def websocket_endpoint(websocket: WebSocket):
     tempo: float = 0.0
     last_beat_reported: float | None = None  # avoid re-reporting same beat
 
+    # Per-connection cue scheduler state (Phase 5 — D-04)
+    show: ShowModel | None = None   # loaded show for cue scheduling
+    fired_ids: set[str] = set()     # cues already dispatched this playback pass
+    is_playing: bool = False         # gate cue scheduling on play state
+
     try:
         while True:
             data = await websocket.receive_text()
@@ -122,14 +132,24 @@ async def websocket_endpoint(websocket: WebSocket):
             elif msg_type == "play":
                 logger.info("[ws] play event at position=%.3f", float(msg.get("position", 0)))
                 last_beat_reported = None  # reset beat tracking on play
+                is_playing = True          # enable cue scheduling
 
             elif msg_type == "pause":
                 logger.info("[ws] pause event at position=%.3f", float(msg.get("position", 0)))
+                is_playing = False  # disable cue scheduling; do NOT modify fired_ids
 
             elif msg_type == "seek":
                 position = float(msg.get("position", 0.0))
                 logger.info("[ws] seek to position=%.3f", position)
                 last_beat_reported = None  # reset so beats near seek target fire
+                # Rebuild fired_ids: mark everything before seek position as fired (D-03)
+                if show is not None:
+                    fired_ids = {
+                        str(cue.id)
+                        for track in show.tracks
+                        for cue in track.cues
+                        if cue.timestamp < position - 0.060
+                    }
 
             elif msg_type == "load":
                 # Browser signals which file is now playing — update beat cache lookup
@@ -146,6 +166,19 @@ async def websocket_endpoint(websocket: WebSocket):
                     else:
                         logger.warning("[ws] no beat data cached for %s", path)
 
+                # Show cue list loading (Phase 5 — D-04)
+                show_id = msg.get("show_id")
+                if show_id:
+                    import lightsync.main as _main
+                    loaded = await _main.show_store.load(show_id)
+                    if loaded:
+                        show = loaded
+                        fired_ids = set()
+                        is_playing = False
+                        logger.info("[ws] loaded show %s with %d tracks", show_id, len(show.tracks))
+                    else:
+                        logger.warning("[ws] show %s not found", show_id)
+
             else:
                 # Unknown message type — echo back for debugging
                 await websocket.send_text(json.dumps({"type": "ack", "echo": msg}))