feat(registry): track repo hyperparameter drift severity

[mkdev5]

Summary

• Closes feat(registry): track repo hyperparameter drift severity #92.
• Adds structured registry hyperparameter drift events with deterministic severity, affected surfaces, and bounded payloads.
• Surfaces high-impact registry drift through upstream status, readiness/admin warnings, and repo-owner registration readiness.
• Updates OpenAPI and regression coverage, including legacy stored snapshot normalization so missing nullable registry fields do not create false drift.

Scope

• This PR is focused and does not mix unrelated backend, UI, MCP, docs, dependency, and deploy changes.
• This follows CONTRIBUTING.md and does not reintroduce GitHub Pages, VitePress, site/, or CNAME.
• I linked an issue, or this is small enough that the summary explains why an issue is not needed.

Validation

• git diff --check
• npm run actionlint
• npm run typecheck
• npm run test:coverage locally; global coverage stays at or above 97% for lines, statements, functions, and branches (aim for 98%+ branch coverage locally so CI variance does not fail near the threshold)
• npm run test:workers
• npm run build:mcp
• npm run test:mcp-pack
• npm run ui:openapi:check
• npm run ui:lint
• npm run ui:typecheck
• npm run ui:build
• npm audit --audit-level=moderate
• New or changed behavior has unit/integration tests for new branches, fallback paths, and sanitizer boundaries

If any required check was skipped, explain why:

• None. npm run test:ci passed locally. Coverage summary: statements 99%, branches 97.01%, functions 98.07%, lines 99.6%.

Safety

• No secrets, wallet details, hotkeys, coldkeys, user PATs, private keys, raw trust scores, private rankings, or private maintainer evidence are exposed.
• Public GitHub text stays sanitized, low-noise, and does not imply compensation guarantees or optimization tactics.
• Auth, cookie, CORS, GitHub App, Cloudflare, or session changes include negative-path tests.
• API/OpenAPI/MCP behavior is updated and tested where needed.
• UI changes use live API data or real empty/error/loading states, not production mock/demo fallbacks.
• Visible UI changes include screenshots or a short recording.
• Public docs/changelogs are updated where needed; changelogs are only edited for release-prep PRs.

Notes

• Registry drift remains internal/admin-facing by default.
• Public forbidden-language safety is covered for generated repo-owner warning text.
• No changelog update: ordinary feature PR per CONTRIBUTING.md.

[JSONbored]

@MkDev11 this is in good shape from the maintainer side.

A few notes:

• The drift summary is wired through the upstream ruleset, API response, OpenAPI schema, generated UI artifact, and readiness warning path.
• The tests cover malformed stored payloads, capped event history, membership drift, legacy optional fields, and the registration-readiness warning path.
• CI is green and the branch merges cleanly with current main.

No code changes requested.