docs(API): add CLAUDE.md with spec workflow guidance #STRINGS-3714

CLAUDE.md

@@ -0,0 +1,25 @@
+# strings-openapi
+
+## Spec changes workflow
+
+1. Before adding a path file or endpoint docs, grep `paths.yaml`, `doc/compiled.json` and `paths/` for the endpoint to confirm it is not already documented under another file name or tag.
+2. Edit the source YAML.
+3. Run `make lint` (runs `swagger-cli validate`, `make bundle`, then `lint.sh`). Do not run a second manual `swagger-cli bundle` afterwards.
+4. `git diff` to confirm scope.
+5. Commit the source change together with the regenerated `doc/compiled.json` (generated but committed). `tmp/compiled.yaml` is gitignored; never stage it.
+
+## Finding endpoints
+
+`paths.yaml` references path files, not literal URLs. Find where an endpoint is wired up with e.g. `grep -n "search.yaml" paths.yaml`.
+
+## Consistency
+
+When adding or editing a request-body property for a resource, apply it to both `paths/<resource>/create.yaml` and `paths/<resource>/update.yaml`, and to the shared response schema under `schemas/`, so POST/PATCH/GET contracts do not drift.
+
+## Breaking changes CI
+
+`.github/workflows/breaking-changes.yml` diffs the compiled spec against the base branch. Adding or reordering enum values, or altering shared response schemas such as `schemas/project_details.yaml`, can fail it. Inspect its diff output before pushing; if it fails on a purely additive enum/field change, explain the additive nature in the PR body instead of re-pushing the same change.
+
+## Commits and PR titles
+
+Use `docs(STRINGS-XXXX): <summary>` for commit messages and PR titles (matches git log history), not the `JIRA-KEY - title` default.