[FLO-13.2c.2] Reject corrupt, changed, stale, and contradictory artifact evidence

[szmyty]

Parent: #46
Parent kit: #29
Roadmap-Step: FLO-Q03
Depends on: #56

Outcome

Close the remaining artifact-correlation adversaries with stable corrupt, changed, stale, and contradictory evidence cases, including protocol-valid provider success followed by host observation or acceptance failure.

Scope

• Add closed, named cases for:
  • changed artifact bytes or identity evidence;
  • corrupt digest/evidence or explicitly synthetic validation corruption;
  • stale run, invocation, binding, or observation correlation; and
  • contradictions across events, results, bindings, and observations.
• Identify the exact owning rejection boundary for every case.
• Use only the accepted public Flow contracts and preserve the existing opaque-token promotion boundaries.
• Determine the smallest contract-safe hardening needed for changed output identity without casually redefining the provisional v1 provenance model.

Acceptance criteria

• Every case has a stable name, explicit trigger, owning boundary, and exact typed outcome.
• Altered bytes/evidence, stale correlation, or contradictory identifiers cannot construct AcceptedArtifactSet.
• Protocol-invalid evidence remains distinguishable from host-observation and artifact-acceptance failures.
• “Corrupt” means digest/evidence corruption or an explicitly synthetic validation failure, not generic provider-native semantic validation by Flow.
• Undeclared files outside bound locators are not described as automatically discovered.
• Evidence and outputs remain deterministic, immutable where required, bounded, offline, and root-confined.
• Focused tests, Rust 1.85, stable Rust, package checks, and repository validators pass.

Non-goals

• Graph execution or production scheduling.
• Real Aniflow, Optiflow, or Renderflow algorithms.
• Generic semantic validation of provider-native formats.
• Durable state, retry, or resume.

[szmyty]

Implemented on draft PR #60 at f521d2b. The checkpoint now covers corrupt result evidence, protocol-valid event/result contradiction, changed and removed evidence after initial observation, stale invocation/binding correlation, and a final typed re-observation gate without changing portable v1 schemas or interpreting free-form provider provenance. CI run #40 is green on Rust 1.85 and stable. This issue remains open until the draft PR is merged.