openapi: selftune/overrides (audit + clear) missing from spec (MCP tools + schemas already exist)

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⚠️ 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

src/api/routes.ts has two live, maintainer-authenticated selftune-override routes, each backed by
an MCP tool with its own Zod output shape in src/mcp/server.ts:

• GET /v1/repos/:owner/:repo/selftune/overrides/audit → loopover_get_selftune_override_audit
  (outputSchema: selftuneOverrideAuditOutputSchema)
• DELETE /v1/repos/:owner/:repo/selftune/overrides → loopover_clear_selftune_override
  (outputSchema: clearSelftuneOverrideOutputSchema)

Neither route appears in src/openapi/spec.ts — grep for selftune in that file returns nothing.
Both are already tested, both already have a CLI mirror in packages/loopover-mcp for the audit
route (#7997), and both have well-defined output shapes in src/mcp/server.ts — the only missing
piece is the OpenAPI documentation.

Requirements

• In src/openapi/schemas.ts, define SelftuneOverrideAuditResponseSchema and
  ClearSelftuneOverrideResponseSchema as z.object({...}) schemas, using
  selftuneOverrideAuditOutputSchema and clearSelftuneOverrideOutputSchema (the raw Zod shapes
  already validated in src/mcp/server.ts) as the field-level source of truth.
• In src/openapi/spec.ts, registry.register both schemas as components, then add
  registerPath entries for GET /v1/repos/{owner}/{repo}/selftune/overrides/audit (with its
  optional limit query param, matching the MCP tool's selftuneOverrideAuditShape) and
  DELETE /v1/repos/{owner}/{repo}/selftune/overrides (with the confirm:true request body the
  route requires).
• Schema is the contract — regenerate and commit. Run npm run ui:openapi after the 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

• SelftuneOverrideAuditResponseSchema and ClearSelftuneOverrideResponseSchema added to
  src/openapi/schemas.ts.
• Both routes registered as OpenAPI paths in src/openapi/spec.ts.
• 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 both 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

Both selftune-override routes are documented in GET /openapi.json /
apps/loopover-ui/public/openapi.json, matching what their MCP tools and CLI mirror already
validate.

Links & Resources

• src/api/routes.ts: GET .../selftune/overrides/audit, DELETE .../selftune/overrides
• src/mcp/server.ts: selftuneOverrideAuditOutputSchema, clearSelftuneOverrideOutputSchema
• src/openapi/spec.ts: /v1/repos/{owner}/{repo}/gate-config/effective registration (pattern to
  mirror)
• 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; feat(mcp): add remote + stdio + CLI surfaces for the selftune override audit #7997 — added the CLI mirror for the
  audit tool

[linear-code]

JSO-6458