engine(focus-manifest): focusManifestToNormalizedJson never serializes publicProof

[JSONbored]

⚠️ Definition of Done: this issue must be completed in full, in a single PR. Do not split this
work across multiple PRs, and do not defer any Deliverable below to a follow-up issue. A PR that
satisfies only some of the Deliverables, stubs a required test, or leaves a checkbox
partially-done does NOT resolve this issue and will be closed.

Context

packages/loopover-engine/src/focus-manifest-validation.ts's focusManifestToNormalizedJson
(lines 63-115) serializes every sub-config of a parsed FocusManifest into a plain JSON object,
using each sub-config's own *ConfigToJson function and only including it when non-null:

const gate = gateConfigToJson(manifest.gate);
if (gate !== null) normalized.gate = gate;
...
const fairnessAnalytics = fairnessAnalyticsConfigToJson(manifest.fairnessAnalytics);
if (fairnessAnalytics !== null) normalized.fairnessAnalytics = fairnessAnalytics;

return normalized;

Every sub-config declared on FocusManifest goes through this pattern — gate, settings,
review, features, contentLane, repoDocGeneration, reviewRecap, maintainerRecap, ops,
publicStats, draftFlow, upstreamDriftIssues, sweepWatchdog, prReconciliation,
activeReviewReconciliation, loopEscalation, federatedIntelligence, experimental,
fairnessAnalytics — except publicProof. publicProofConfigToJson (exported from
focus-manifest.ts at line 2535, the exact same { present, enabled } → JsonValue | null shape as
its sibling publicStatsConfigToJson) is never imported into focus-manifest-validation.ts and
never called. Grepping the file for publicProof returns zero matches.

focusManifestToNormalizedJson backs buildFocusManifestValidation — the offline validator behind
the loopover_validate_config MCP tool, the config-lint route, and the admin dry-run write path
(confirmed via focus-manifest-validation.ts's own imports/exports). Today, when an operator
configures publicProof: in their manifest and runs the validator to check what the manifest
actually resolves to, the publicProof block is silently absent from the normalized output — even
though parseFocusManifest parsed it correctly — giving the operator no visibility that the field
was recognized at all. Note this is distinct from config-lint.ts's lintManifestText, which uses
a separate known-field-name list that DOES include "publicProof" (line 4431 of focus-manifest.ts)
— so the warning-level check is unaffected; this issue is specifically about the normalized-JSON
output being incomplete.

Requirements

• In packages/loopover-engine/src/focus-manifest-validation.ts, import publicProofConfigToJson
  from ./focus-manifest.js alongside the other *ConfigToJson imports (lines 1-20).
• In focusManifestToNormalizedJson, add the same pattern used for every other sub-config:

  const publicProof = publicProofConfigToJson(manifest.publicProof);
  if (publicProof !== null) normalized.publicProof = publicProof;

  placed alongside the other sub-config serializations (position doesn't matter functionally, but
  keep it grouped with the others for readability).
• Do not change any other sub-config's serialization, and do not change
  publicProofConfigToJson/parsePublicProofConfig in focus-manifest.ts.

Deliverables

• A manifest with publicProof: { enabled: true } produces a focusManifestToNormalizedJson
  result whose publicProof field equals { enabled: true }.
• A manifest with no publicProof block (or an invalid one that falls back to { present: false, enabled: false }) produces a result with no publicProof key at all — matching how every
  other absent sub-config is already omitted rather than emitted as null/false.

Both Deliverables are required in this one PR — there is no narrower scope for this issue.

Test Coverage Requirements

packages/loopover-engine/src/** is measured by Codecov via two separate uploads whose hits are
unioned — root test/** AND packages/loopover-engine/test/**. Add the regression test to
test/unit/focus-manifest-validation.test.ts (root-level, this file's existing test location),
asserting both Deliverables above against buildFocusManifestValidation's (or
focusManifestToNormalizedJson's, whichever is exported/testable) actual output. Target 100% branch
coverage of the new serialization branch.

Expected Outcome

focusManifestToNormalizedJson's output includes publicProof whenever it is configured, matching
every other sub-config, so the offline validator (loopover_validate_config, the config-lint route,
the admin dry-run write path) gives an operator accurate visibility into a configured publicProof:
block.

Links & Resources

• packages/loopover-engine/src/focus-manifest-validation.ts (lines 1-20 imports, lines 63-115
  focusManifestToNormalizedJson)
• packages/loopover-engine/src/focus-manifest.ts (line 2535 publicProofConfigToJson, line 4431
  the separate known-field-name list already including "publicProof")
• test/unit/focus-manifest-validation.test.ts
• Related/adjacent gap in the same feature area: the issue filed alongside this one for
  parseFocusManifest's "no recognized fields" fallback also missing publicProof
• Original feature: Public proof page /proof/:owner/:repo + README badge — the shareable verification surface #9569
• Milestone: Miner Wave 4.6 — AMS Hardening Round 3

[linear-code]

JSO-7356