Fix shared-skill packing and restore review-panel availability

[Copilot]

Description

The review workflow installed apm-review-panel but dropped its shared skill directory during packing, leaving a green run without a review. APM 0.30.0 alone retains the same defect.

• Packaging: Derive default pack prefixes from primitive deployment directories, preserving shared skills without including unrelated shared-root content. Explicit prefix overrides remain unchanged.
• Workflow: Pin the panel to APM 0.30.0 with temporary copilot,agent-skills targeting and regenerate its lock. Leave the shared 0.28.0 default unchanged.
• Guardrails: Fail before inference if the panel or required assets are missing or empty. Add byte-for-byte install/archive/restore checks, regression coverage, and an architecture boundary guard.
• Rollout: Document the fresh post-merge panel dispatch and retain the workaround until a release includes the permanent fix.

Type of change

• Bug fix
• New feature
• Documentation
• Maintenance / refactor

Testing

• Tested locally
• All existing tests pass
• Added tests for new functionality (if applicable)

Spec conformance (OpenAPM v0.1)

Legacy bundle filtering and workflow provisioning only; no changes to normative formats or target deployment rules.

• Spec edit: docs/src/content/docs/specs/openapm-v0.1.md updated
  (new/changed <a id="req-XXX"></a> anchor + prose + Appendix C
  row).
• Manifest edit: docs/src/content/docs/specs/manifests/openapm-v0.1.requirements.yml
  updated.
• Test edit: a @pytest.mark.req("req-XXX") test under
  tests/spec_conformance/ added or extended.
• CONFORMANCE.{md,json} regenerated via
  uv run --extra dev python -m tests.spec_conformance.gen_statement
  and committed.
• N/A -- this PR does not change OpenAPM-observable behaviour.