Add cardonnay-sync skill

.claude/skills/cardonnay-sync/SKILL.md

@@ -0,0 +1,90 @@
+---
+name: cardonnay-sync
+description: >-
+  Sync cardano-node-tests to a specific cardonnay branch/ref so a real test
+  run actually exercises it, instead of a stale PyPI release. Use whenever
+  making or verifying changes in the cardonnay repo (cluster scripts, genesis
+  spec files, cost models) that need to be exercised via a cardano-node-tests
+  test run, or whenever a test result needs to be trusted before reporting it
+  as "verified" or "passing."
+---
+
+# Syncing cardano-node-tests to a cardonnay branch
+
+`cardano-node-tests` depends on `cardonnay` as a normal Python package,
+pinned in `pyproject.toml` to a version range and locked in `uv.lock` to one
+specific PyPI release. Editing files in a local `cardonnay` git clone, even
+an editable pip install of it, does not change what a real test run uses
+unless you wire it to that ref explicitly. `runner/node_upgrade.sh` and
+friends build a fresh, isolated venv from `pyproject.toml` + `uv.lock` only,
+they have no idea a local `/path/to/cardonnay` clone exists.
+
+## When this skill is invoked, do this immediately
+
+1. If a branch/ref was given as an argument, use it. Otherwise ask the user
+   which cardonnay branch, tag, or commit to sync to before doing anything
+   else. Do not guess or default to `master` silently, confirm it.
+2. Run the sync procedure below against that ref, in `cardano-node-tests`.
+3. Verify it actually took effect (step 4 of the procedure), don't just
+   report success because the commands didn't error.
+4. Report back the resolved commit hash and version string so the user can
+   see exactly what got pinned.
+5. Remind the user this is a temporary, local-only change (see step 7) and
+   confirm whether they want it left in place for an upcoming test run or
+   reverted now.
+
+Do not run any cardano-node-tests test (`runner/node_upgrade.sh`,
+`make start-cluster`, etc.) on a cardonnay change without having gone through
+this sync first in the same session. If a test result is already reported
+from before this sync ran, treat it as unverified. An editable local
+install, a `git pull` in the cardonnay clone, or "I have the right branch
+checked out" are not sufficient by themselves.
+
+## The sync procedure
+
+1. Confirm the branch/ref exists and is pushed (or use `master` if it's
+   already merged there but not yet released to PyPI). If the user asked for
+   a branch, use exactly that branch, not `master`.
+
+2. In `cardano-node-tests/pyproject.toml`, temporarily change the dependency
+   line from a version pin to a git reference:
+
+   ```
+   "cardonnay @ git+https://github.com/IntersectMBO/cardonnay.git@<branch-or-master>",
+   ```
+
+3. Regenerate the lock file so it actually resolves that ref. This needs
+   `uv`, which lives in the Nix dev shell, not necessarily on bare `PATH`:
+
+   ```sh
+   nix develop --accept-flake-config . -c bash -c "make update-uv-lock"
+   ```
+
+4. Confirm the lock file actually changed, don't just assume the command
+   succeeded silently. `uv` prints a line like:
+
+   ```
+   Updated cardonnay v0.4.1 -> v0.4.2.dev8+gca7c6fb56 (ca7c6fb5)
+   ```
+
+   The commit hash at the end must match the tip of the branch you pushed.
+   If the version number didn't change, the wiring didn't take, stop and find
+   out why before running anything.
+
+5. Clear any previously-built test venv before the next run, otherwise a
+   stale one gets reused:
+
+   ```sh
+   rm -rf run_workdir/.venv
+   ```
+
+6. Now run the actual test (`runner/node_upgrade.sh`, or a plain
+   `make cluster-scripts && make start-cluster` for a quicker smoke check).
+   This is the first point where it's actually exercising the real change.
+
+7. Treat this `pyproject.toml`/`uv.lock` edit as strictly temporary, local
+   only. Never commit or push it as part of a real PR. Once the cardonnay
+   change is confirmed working and merged, revert both files back to the
+   normal version-pin form (`git checkout -- pyproject.toml uv.lock`, or
+   re-run `make update-uv-lock` after reverting the dependency line). A real
+   version bump only happens once cardonnay cuts an actual PyPI release.