test(vtt-thumbnail): [PKG-VTT-THUMB-02] reproduce parsing and lifecycle failures

refactor/risks.json

@@ -4149,7 +4149,9 @@
       "evidence": [
         "refactor/baselines/vtt-thumbnail-release.json",
         "refactor/baselines/vtt-thumbnail-contract.md",
-        "refactor/scripts/vtt-thumbnail-contract.test.mjs"
+        "refactor/scripts/vtt-thumbnail-contract.test.mjs",
+        "test/vtt-thumbnail.test.js",
+        "refactor/baselines/vtt-thumbnail-failures.json"
       ],
       "compatibleResolution": "Preserve valid cue selection and geometry; test malformed data and standard VTT separately from old compiler defects.",
       "closureCriteria": "Parser fixtures include malformed, empty, real demo VTT, fractional and shared bounds, relative URLs and historical accepted formats."
@@ -4157,7 +4159,7 @@
     {
       "id": "VTT-THUMB-LIFE-01",
       "title": "Fetch completion, setBar listeners and mobile timers have no destroy ownership",
-      "confirmation": "source-observed",
+      "confirmation": "reproduced",
       "status": "open",
       "owners": [
         "PKG-VTT-THUMB-02",
@@ -4167,7 +4169,9 @@
       "evidence": [
         "refactor/baselines/vtt-thumbnail-release.json",
         "refactor/baselines/vtt-thumbnail-contract.md",
-        "refactor/scripts/vtt-thumbnail-contract.test.mjs"
+        "refactor/scripts/vtt-thumbnail-contract.test.mjs",
+        "test/vtt-thumbnail.test.js",
+        "refactor/baselines/vtt-thumbnail-failures.json"
       ],
       "compatibleResolution": "Own requests, listeners, timers and controls per registration without stale writes or cross-instance cleanup.",
       "closureCriteria": "Deferred request, destroy, failure, timer, repeated registration and native core scenarios demonstrate cleanup."