openapi: 5 repo maintainer-report routes missing from spec (maintainer-noise, ams-miner-cohort, gate-precision, outcome-calibration, activation-preview)

[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.

⚠️ Required pattern: mirror how GET /v1/repos/{owner}/{repo}/gate-config/effective is documented
in src/openapi/spec.ts — issue #6611 fixed the exact same class of gap for that route.

Context

Five GET /v1/repos/:owner/:repo/* maintainer-report routes in src/api/routes.ts are all live,
maintainer-authenticated, and each already has an MCP tool with its own Zod output shape in
src/mcp/server.ts — but none of the five appears in src/openapi/spec.ts:

• .../maintainer-noise → loopover_get_maintainer_noise. Its response schema,
  MaintainerNoiseReportSchema, is even already imported into spec.ts and
  registry.register("MaintainerNoiseReport", MaintainerNoiseReportSchema)'d as a component — it is
  simply never attached to a registerPath, so it's orphaned in the components section and
  unreachable from paths.
• .../ams-miner-cohort → loopover_get_ams_miner_cohort. Same situation: AmsMinerCohortComparisonSchema
  is registered as a component but never attached to a path.
• .../gate-precision → loopover_get_gate_precision (outputSchema: gatePrecisionOutputSchema,
  no OpenAPI schema exists yet).
• .../outcome-calibration → loopover_get_outcome_calibration (outputSchema: maintainerMeasurementReportOutputSchema, no OpenAPI schema exists yet).
• .../activation-preview → loopover_get_activation_preview (outputSchema: activationPreviewOutputSchema, no OpenAPI schema exists yet).

All five share the same owner/repo path params and maintainer-only auth boundary as their
already-documented sibling .../gate-config/effective and .../live-gate-thresholds (#6611 fixed
this same class of gap for .../gate-config/effective).

Requirements

• For maintainer-noise and ams-miner-cohort: the response schemas already exist
  (MaintainerNoiseReportSchema, AmsMinerCohortComparisonSchema, already registry.register'd in
  src/openapi/spec.ts) — just add the missing registry.registerPath({...}) entries for
  GET /v1/repos/{owner}/{repo}/maintainer-noise and GET /v1/repos/{owner}/{repo}/ams-miner-cohort.
• For gate-precision, outcome-calibration, and activation-preview: define new
  z.object({...}) schemas in src/openapi/schemas.ts (GatePrecisionResponseSchema,
  OutcomeCalibrationResponseSchema, ActivationPreviewResponseSchema), using
  gatePrecisionOutputSchema, maintainerMeasurementReportOutputSchema, and
  activationPreviewOutputSchema (the raw Zod shapes already validated in src/mcp/server.ts) as
  the source of truth, registry.register them, then add registerPath entries for their three
  routes.
• All five paths take owner/repo path params and (where applicable) the same optional
  windowDays query param their MCP tool siblings accept — mirror the request shape
  .../gate-config/effective and .../live-gate-thresholds already use.
• Schema is the contract — regenerate and commit. Run npm run ui:openapi after the schema/spec
  edits and commit the regenerated apps/loopover-ui/public/openapi.json in this same PR. CI
  enforces this via npm run ui:openapi:check (part of npm run test:ci).

Deliverables

• registerPath entries added for all five routes in src/openapi/spec.ts.
• Three new response schemas added to src/openapi/schemas.ts for gate-precision,
  outcome-calibration, and activation-preview, matching their MCP tools' output shapes
  field-for-field.
• apps/loopover-ui/public/openapi.json regenerated via npm run ui:openapi and committed.
• npm run ui:openapi:check passes in CI.

All deliverables are required in this one PR — there is no follow-up issue.

Test Coverage Requirements

99%+ Codecov patch target (codecov/patch, unsharded via npm run test:coverage) on any new schema
helper code. Add a regression test asserting all five paths appear in buildOpenApiSpec()'s output
with the correct method and a response schema whose keys match each route's MCP tool output shape.

Expected Outcome

All five maintainer-report routes are documented in GET /openapi.json /
apps/loopover-ui/public/openapi.json, matching what their MCP tool counterparts already validate —
closing the drift for the entire "repo maintainer advisory report" route family in one pass.

Links & Resources

• src/api/routes.ts: the five GET /v1/repos/:owner/:repo/* routes above
• src/mcp/server.ts: MaintainerNoiseReportSchema, AmsMinerCohortComparisonSchema,
  gatePrecisionOutputSchema, maintainerMeasurementReportOutputSchema, activationPreviewOutputSchema
• src/openapi/spec.ts: /v1/repos/{owner}/{repo}/gate-config/effective registration (pattern to
  mirror); the two already-registered-but-orphaned component schemas noted above
• OpenAPI spec is missing GET /v1/repos/{owner}/{repo}/gate-config/effective (documented sibling: live-gate-thresholds) #6611 — the precedent issue for this exact class of gap

[linear-code]

JSO-6457