chore(ci): quarantine enterprise-shaped-scenarios to workflow_dispatc…

[LalaSkye]

…h (Refs #22)

enterprise-execution-readiness/ is not part of the v0.1.0 proof surface.

All 4 tests under enterprise-execution-readiness/tests/ have errored at pytest collection on every run since 2026-05-12 (10/10 reds) with AttributeError: 'NoneType' object has no attribute 'dict' from a @DataClass decoration in enterprise-execution-readiness/adapters/replay_ledger.py:14 (Python 3.11.15, dataclasses.py:712, _is_type).

This commit restricts enterprise-shaped-scenarios.yml to workflow_dispatch only, so that main returns to fully green and v0.1.0 release hygiene (PR-B) can proceed. The underlying dataclass bug is tracked in #22 and will be fixed in a separate branch against a green main.

Refs #22

Change class

• code primitive
• governance claim
• invariant
• adversarial vector
• receipt / audit surface
• documentation only

Boundary check

• This change does not widen public claims without evidence.
• This change does not extend EXIT_ENUM.
• This change does not weaken scope monotonicity.
• This change does not allow unresolved state to bind into execution.

Proof surface

• Tests or verifier command updated where needed.
• Build receipt updated where needed.
• CI green proof is not claimed unless observed.