fix(engine): include fairnessAnalytics in parseFocusManifest's emptiness check - #8414

Summary

parseFocusManifest's aggregate condition (deciding whether to emit a "no recognized focus fields" warning and force manifest.present = false) checks !manifest.X.present for every other optional block (gate, publicStats, draftFlow, ... federatedIntelligence), but omitted fairnessAnalytics even though it's parsed and assigned identically to every sibling block.

Concrete failure: a .loopover.yml containing only a populated fairnessAnalytics: block (e.g. fairnessAnalytics: { enabled: true }) was correctly parsed into manifest.fairnessAnalytics = { present: true, enabled: true }, but the aggregate check never saw it, so the manifest was still incorrectly forced to present: false with a misleading "no recognized focus fields" warning.

Fix

Added the missing !manifest.fairnessAnalytics.present term, in the same relative position fairnessAnalytics is parsed in (between publicStats and draftFlow). No other block's condition or parseFairnessAnalyticsConfig itself was touched.

Added a dedicated fairnessAnalytics: test block mirroring the existing publicStats: suite exactly -- this block had zero test coverage before this PR (confirmed: no existing test referenced parseFairnessAnalyticsConfig or the fairnessAnalytics field at all beyond an unrelated settings-alias fixture), including the specific regression case this issue describes.

Scope

• The PR title follows type(scope): short summary Conventional Commit format.
• This PR's primary change is focused on parseFocusManifest's emptiness check omits fairnessAnalytics, misreporting present:false #8366.
• This follows CONTRIBUTING.md and does not reintroduce GitHub Pages, VitePress, site/, or CNAME.
• I linked a currently open issue this PR resolves.

Fixes #8366

Validation

• git diff --check
• npm run actionlint (no workflow changes)
• npm run typecheck (clean)
• npx vitest run test/unit/focus-manifest.test.ts -- 792/792 passing (9 new tests)
• Coverage verified via --coverage.include="packages/loopover-engine/src/focus-manifest.ts": the new line is not in the uncovered-lines list; all pre-existing uncovered lines are unrelated to this diff
• npm run docs:drift-check -- passes (102 FocusManifest fields all documented, unchanged field count since this adds a check, not a new field)
• npm run ui:openapi:check (no API/schema changes)
• npm audit --audit-level=moderate (no dependency changes)
• New or changed behavior has unit/integration tests for new branches, fallback paths, and sanitizer boundaries

If any required check was skipped, explain why: no workflow, API, OpenAPI, or dependency surface is touched -- this is a one-line condition fix plus its own dedicated test block in packages/loopover-engine.

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. (N/A -- no such changes.)
• API/OpenAPI/MCP behavior is updated and tested where needed. (N/A -- no API/OpenAPI/MCP changes.)
• UI changes use live API data or real empty/error/loading states, not production mock/demo fallbacks. (N/A -- no UI changes.)
• Visible UI changes include a UI Evidence section below with JPG/JPEG or PNG screenshots. (N/A -- zero apps/loopover-ui/** or any visual-surface changes in this PR.)
• Public docs/changelogs are updated where needed; changelogs are only edited for release-prep PRs.