Turn captions off for real

cc_load_policy is only a request: the viewer's "always show captions"
preference overrides it, and auto-generated tracks ignore it. Unloading
the caption module is the part that sticks, and it has to run again after
every load because a new video brings the module back.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01H9v2Xoa6eoeGYpK6gp95k9

public/player/yt.js

@@ -25,9 +25,28 @@ const PLAYER_VARS = {
   playsinline: 1,
   iv_load_policy: 3,
   fs: 0,
-  cc_load_policy: 0, // no burned-in captions over the visuals
+  cc_load_policy: 0, // asks for no captions; see hideCaptions for the rest
 };
 
+/**
+ * Turn captions off for real.
+ *
+ * cc_load_policy is only a request: the viewer's "always show captions"
+ * preference overrides it, and auto-generated tracks ignore it outright.
+ * Unloading the module is the part that sticks. Two names because the module
+ * is 'captions' on the HTML5 player and 'cc' on the older one, and loading a
+ * new video resets both — so this has to run again after every load.
+ */
+export function hideCaptions(player) {
+  for (const module of ['captions', 'cc']) {
+    try {
+      player.unloadModule(module);
+    } catch {
+      // Module was never loaded for this video; nothing to turn off.
+    }
+  }
+}
+
 /**
  * Create a player in the given element id. Resolves once the player is ready.
  * `onStateChange` receives the raw YT state code.
@@ -41,8 +60,18 @@ export async function createPlayer(elementId, { onStateChange } = {}) {
       height: '100%',
       playerVars: { ...PLAYER_VARS, origin: location.origin },
       events: {
-        onReady: () => resolve(player),
-        onStateChange: (event) => onStateChange?.(event.data, player),
+        onReady: () => {
+          hideCaptions(player);
+          resolve(player);
+        },
+        onStateChange: (event) => {
+          // The caption module comes back with each new video, and only once
+          // the video is actually running, so re-clear it here.
+          if (event.data === STATE.PLAYING || event.data === STATE.CUED) {
+            hideCaptions(player);
+          }
+          onStateChange?.(event.data, player);
+        },
       },
     });
   });