browser/openspec/changes/add-scum-ue4ss-dll-runtime-extension/tasks.md

1. Plugin and Platform contracts

• 1.1 Add the typed UE4SS DLL extension declaration to plugin schema, validator, fixtures, and the SCUM manifest with Windows-only compatibility metadata and an inactive unpublished-release guard.
• 1.2 Add domain, DTO, validator, and safe API projection types for declared DLL extensions and frozen start-job extension plans.
• 1.3 Freeze compatible extension plans into SCUM process.start jobs and reject incompatible Linux endpoint plans before Run dispatch.
• 1.4 Add focused Platform tests for registration, safe projection, start-job fencing, and unsupported-platform behavior.

2. Management console

• 2.1 Extend typed frontend API/schema contracts for safe DLL extension declarations.
• 2.2 Render the declared Windows-only UE4SS extension and update-on-start policy in existing plugin/server detail surfaces without paths or secrets.
• 2.3 Add focused frontend tests for declaration rendering and Linux unsupported state.

3. Independent Run extension synchronization

• 3.1 Mirror the frozen extension plan in the independent Run protocol and validate bounded, Windows-only DLL fields.
• 3.2 Implement scoped staged DLL download, checksum verification, managed-release marker, atomic activation, previous-DLL rollback, generated UE4SS mod configuration, and deterministic mods index update.
• 3.3 Gate process.start on extension synchronization and fail closed on non-Windows targets, unsafe payloads, or missing UE4SS layout without executing/loading the DLL directly.
• 3.4 Add Run unit tests for update/no-op/rollback/Linux rejection and channel independence.

4. Verification and delivery

• 4.1 Run manifest, Platform, frontend, and Run focused tests; run openspec validate add-scum-ue4ss-dll-runtime-extension --strict and scripts/check-structure.sh.
• 4.2 Review scoped diffs, stage only task files in browser and independent Run repositories, commit, and push both configured branches.