docs: add vote tracking endpoints to API documentation

Update REST endpoint docs (votes.md, sessions.md), WebSocket protocol
(websocket.md), OpenAPI spec, and voting guide with the new
GET /api/votes, GET /api/sessions/:id/votes, and vote.received event.

Made-with: Cursor

docs/api/guides/voting-and-popularity.md

@@ -67,6 +67,17 @@ A bot sends individual votes during the stream. Each vote is processed immediate
 
 See [Votes live endpoint](../endpoints/votes.md#post-apivoteslive).
 
+**Real-time tracking:** Live votes also broadcast a `vote.received` WebSocket event to all clients subscribed to the active session. This enables stream overlays and bots to react to votes in real-time without polling. See [WebSocket vote.received](../websocket.md#votereceived).
+
+---
+
+## 3b. Querying Vote Data
+
+Two endpoints expose vote data for reading:
+
+- **`GET /api/sessions/{id}/votes`** — Per-game vote breakdown for a session. Returns aggregated `upvotes`, `downvotes`, `net_score`, and `total_votes` per game. See [Sessions votes endpoint](../endpoints/sessions.md#get-apisessionsidvotes).
+- **`GET /api/votes`** — Paginated global vote history with filtering by `session_id`, `game_id`, `username`, and `vote_type`. Returns individual vote records. See [Votes list endpoint](../endpoints/votes.md#get-apivotes).
+
 ---
 
 ## 4. Timestamp Matching Explained