Define concrete document parser isolation rollout and invariants

docs/ROADMAP.md

@@ -105,6 +105,7 @@ release. Keep their evidence and unchecked production gates intact.
   decode; broader codec/ABI coverage and desktop packaging remain open.
 - [ ] CPU OCR, image retrieval, audio transcription, video segment locations.
 - [ ] Isolated extraction workers with timeouts and resource ceilings.
+  See [implementation subgoals and provenance contract](EXTRACTION-ISOLATION.md).
 
 ## 5. Release gates
 - [x] Normal worker build/staging defaults to hardware-detecting auto with CPU