fix(jassub): [PKG-JASSUB-10] release bitmap batches on rendering errors

refactor/risks.json

@@ -2,7 +2,7 @@
   "schemaVersion": 1,
   "task": "BASE-07",
   "sourceCommit": "e01f39ff",
-  "updatedAt": "2026-09-14T06:00:35.506Z",
+  "updatedAt": "2026-09-14T07:23:15.393Z",
   "note": "Open means closure evidence is outstanding; source-observed and unverified are not reproduced runtime bugs. A source issue already mitigated in the workspace still requires candidate regression evidence. No accepted-with-scope item is implied by baseline task completion.",
   "items": [
     {
@@ -6102,6 +6102,31 @@
         "refactor/baselines/multiple-subtitles-ass-validation.json"
       ],
       "resolutionRationale": "Frozen main output fails before repair while same-version legacy/source remain correct. Exact-output repair preserves valid/custom output and exception ownership.315 package checks, actual main/legacy unit cases and source/main/legacy each21 native desktop cases prove this specific conversion defect fixed, without claiming full ASS layout, device or source-seek acceptance."
+    },
+    {
+      "id": "JASSUB-RENDER-RESOURCES-01",
+      "title": "Main-thread async rendering leaves received ImageBitmaps open when native canvas operations throw",
+      "confirmation": "reproduced",
+      "status": "resolved",
+      "owners": [
+        "PKG-JASSUB-10"
+      ],
+      "evidence": [
+        "test/jassub-offscreen.test.js",
+        "test/browser/jassub-render-failure.spec.js",
+        "refactor/changes/2026-09-14-PKG-JASSUB-10-render-resources.md",
+        "refactor/baselines/jassub-render-validation.json"
+      ],
+      "compatibleResolution": "Release all owned async bitmaps in finally, preserving the original native exception, ordinary draw order and synchronous pixel buffer behavior.",
+      "closureCriteria": "Controlled clear/resize/first/later draw failures and actual native Canvas failure release all bitmaps; normal rendering, subsequent subtitle recovery, source/built regressions, provenance and strict types pass.",
+      "workspaceState": "Final main/legacy release all owned bitmaps on native drawing failure; normal main-thread subtitle playback and explicit redraw recovery pass on three desktop engines. Firefox offscreen stall remains separate.",
+      "resolutionEvidence": [
+        "refactor/baselines/jassub-render-validation.json",
+        "refactor/changes/2026-09-14-PKG-JASSUB-10-render-resources.md",
+        "test/jassub-offscreen.test.js",
+        "test/browser/jassub-render-failure.spec.js"
+      ],
+      "resolutionRationale": "Old exact main fails all four controlled disposal cases and all three native batch-disposal cases. Candidate full suite passes 201 cases; actual main/legacy runtime groups each pass 69 cases and each has 12 native failure/recovery/playback cases. The fix changes only async bitmap release on main-thread render and retains exceptions and synchronous buffers."
     }
   ]
 }