fix(capabilities): use canonical catalog opt-in

[artiphishle]

Summary

• use src/capabilities/index.ts as the sole local capability-catalog opt-in
• preserve unrelated package.json#ankh metadata and reject stale published capability metadata
• run packed catalog parity only when published ankh.capabilities exists

Validation

• bun test src/tools/package/resolvePackageCapabilitiesAsync.test.ts src/tools/workflows/releaseVerification.test.ts
• bun run build
• bun run typecheck
• bun run lint (0 errors; 42 existing warnings)
• bun run knip:check (existing configuration hint)
• bun test (177 passed; 6 existing macOS temporary-directory realpath failures in APM packed-artifact tests)
• bun run changeset:status
• bun run format:check
• bun run docs:check

Closes #595

[artiphishle]

Review on c4617b4: the stale-metadata and unrelated-ankh.structure fixes are correct, but there is one merge blocker.

resolvePackageCapabilitiesAsync() now treats the existence of src/capabilities/index.ts as requiring package.json#ankh. That breaks the intentional @ankhorage/api case documented by the rollout audit: API publishes a public empty static CAPABILITIES surface for composition, while executable operations are dynamically projected and the package intentionally has no static ankh.capabilities discovery metadata.

Required behavior:

• source absent + no ankh.capabilities -> no materialization;
• source absent + stale ankh.capabilities -> deterministic error;
• source present + ankh discovery metadata -> materialize/synchronize;
• source present + no ankh discovery metadata -> allow the public/source catalog to exist without forcing static discovery metadata (API-like dynamic-only package).

Please replace the current "canonical source requires package.json ankh discovery metadata" regression with an API-like source-only regression, and keep packed parity conditional on actual published ankh.capabilities.

No package-name special case. After that, rebase on current main because this draft is already behind active Devtools work and rerun full CI.

[artiphishle]

Review status: the canonical opt-in design is correct and matches Doctor: src/capabilities/index.ts is the capability-participation signal, unrelated ankh.* metadata is preserved, stale ankh.capabilities without a source catalog is rejected, and packed parity is skipped only when no published capability metadata exists.

Keep this PR Draft until PR #604 is integrated and the full suite is green. This PR is also the required base for issue #601 because both touch the packed parity/release-template path; #601 should build on the rebased #597 result rather than create a competing release.yml implementation.