Fix skill merge metadata drift

[rodaddy]

Summary

• refresh generated YAML frontmatter during generate-skills --conflict=merge while preserving manual content outside generated markers
• write schema_hash from the same full-description schema surface used by skills list
• add a regression test for old generated skills that lacked metadata

Validation

• bun test tests/integration/generate-skills.test.ts tests/cli/skills.test.ts tests/cli/generate-skills.test.ts
• bun run typecheck
• built patched local binary and regenerated Open Brain skill bundle
• mcp2cli skills list now reports open-brain ok 44 tools
• mcp2cli skills diff open-brain reports no changes detected

Rollout note

This is needed for the Open Brain repo-facts contract rollout because the generated Open Brain mcp2cli bundle already contained get_contract, upsert_repo_fact, and list_repo_facts, but existing bundles regenerated with --conflict=merge kept old frontmatter and stayed falsely marked stale.

[rodaddy]

Controller validation for final head b3281156dcb88dbc22665dd038a612ef94093020:

• Fixed remaining frontmatter edge case: inline YAML trigger arrays are preserved during --conflict=merge.
• Added regression coverage in tests/generation/file-manager.test.ts.
• bun test tests/generation/file-manager.test.ts tests/cli/skills.test.ts tests/integration/generate-skills.test.ts -> 48 pass.
• bun run typecheck -> pass.
• bun test -> 1050 pass, 0 fail.
• Rebuilt local binary and verified Open Brain skill generation/status:
  • mcp2cli --version -> 0.3.7
  • mcp2cli generate-skills open-brain --conflict=merge -> generated 44-tool bundle.
  • mcp2cli skills list | rg open-brain -> open-brain ok 44 tools.
  • mcp2cli skills diff open-brain -> no changes detected.
• GitHub checks: CI check pass, GitGuardian pass.

Final worker verification is running after the inline-trigger fix.