fix: improve yomitan keyboard navigation and payload handling

launcher/aniskip-metadata.test.ts

@@ -166,7 +166,9 @@ test('buildSubminerScriptOpts includes aniskip payload fields', () => {
   assert.match(opts, /subminer-aniskip_intro_end=62/);
   assert.match(opts, /subminer-aniskip_lookup_status=ready/);
   assert.ok(payloadMatch !== null);
-  const payload = JSON.parse(decodeURIComponent(payloadMatch[1]));
+  assert.equal(payloadMatch[1].includes('%'), false);
+  const payloadJson = Buffer.from(payloadMatch[1], 'base64url').toString('utf-8');
+  const payload = JSON.parse(payloadJson);
   assert.equal(payload.found, true);
   const first = payload.results?.[0];
   assert.equal(first.skip_type, 'op');

launcher/aniskip-metadata.ts

@@ -532,7 +532,9 @@ function buildLauncherAniSkipPayload(aniSkipMetadata: AniSkipMetadata): string |
       },
     ],
   };
-  return encodeURIComponent(JSON.stringify(payload));
+  // mpv --script-opts treats `%` as an escape prefix, so URL-encoding can break parsing.
+  // Base64url stays script-opts-safe and is decoded by the plugin launcher payload parser.
+  return Buffer.from(JSON.stringify(payload), 'utf-8').toString('base64url');
 }
 
 export function buildSubminerScriptOpts(