feat(resolve): add deterministic R1 artifact tracer

[avabbbb]

Summary

• Add runtime.test.fixture-image, a deterministic no-provider task that persists the repository PNG fixture through the existing Runtime task ledger and worker.
• Add artifact.locate --task-id, which only returns completed Runtime artifacts after validating store containment, MIME type, file size, and SHA-256. read_artifact now performs the same integrity checks.
• Document a same-machine Resolve R0/R1 tracer using Resolve native MCP plus the existing Flovart CLI. It is explicitly a local fixture, not AI generation from the selected clip.

Local verification

• cargo test --manifest-path src-tauri/Cargo.toml --test resolve_r1_artifact -- --nocapture — 3/3 pass; used TAURI_CONFIG={"bundle":{"externalBin":[]}} because this worktree has no Agent sidecar.
• npx vitest run tests/flovartRuntimeTasks.test.ts tests/flovartRuntimeRegistry.test.ts tests/studioInspector.test.ts — 23/23 pass.
• npx tsc --noEmit — pass after installing the locked DSH plugin dependencies.
• npm run docs:check — pass, 151 documents.
• npm run studio:build — pass as package generation only; it reports missing AE SDK and Resolve WorkflowIntegration.node.

Limitations

No real Resolve Studio 21.1 native-MCP connection or Media Pool import has been verified. The CLI returns a verified durable local path for a completed Runtime task, but its handoff to Resolve is still untested. The fixture is public/favicon.png; it is not a generated scene and does not use the selected clip. Browser Workflow artifacts still have no large-file binary handoff. Do not treat this PR as a completed Resolve vertical slice.