Add new privateRegistries category (6 endpoints)

[ldraney]

Parent Issue

#86 — Expand Octokit coverage

Category: privateRegistries (NEW — no file exists yet)

File to create: src/tools/categories/privateRegistries.ts

Methods to Add (6)

Method	Route
createOrgPrivateRegistry	POST /orgs/{org}/private-registries
deleteOrgPrivateRegistry	DELETE /orgs/{org}/private-registries/{secret_name}
getOrgPrivateRegistry	GET /orgs/{org}/private-registries/{secret_name}
getOrgPublicKey	GET /orgs/{org}/private-registries/public-key
listOrgPrivateRegistries	GET /orgs/{org}/private-registries
updateOrgPrivateRegistry	PATCH /orgs/{org}/private-registries/{secret_name}

Setup Required

1. Create src/tools/categories/privateRegistries.ts
2. Export privateRegistriesCategory from src/tools/categories/index.ts
3. Add to ALL_CATEGORIES in src/tools/generator.ts
4. Add to full and org-admin presets

Tool name format: github_private_registries_<snake_case_method>.

Acceptance Criteria

• New file created with all 6 methods
• Registered in generator.ts
• npm run build passes
• TOOLS.md updated