{"changes":[{"id":"001-remove-estimate-endpoint","category":"remove-endpoint","severity":"breaking","versionBump":"major","description":"Remove POST /auto/estimate. Existing callers will get 404. (Real-world equivalent: deprecation cycle finished and the endpoint is gone.)","applied":false},{"id":"002-add-optional-coverage-tier","category":"add-optional-field","severity":"additive","versionBump":"minor","description":"Add optional coverage_tier (basic|standard|premium) to POST /auto/estimate body. Existing callers unaffected.","applied":false},{"id":"003-require-x-carrier-key","category":"add-required-header","severity":"breaking","versionBump":"major","description":"Require X-Carrier-Key header on POST /auto/estimate. Naive callers will fail header validation.","applied":false}]}