ci(justfile): use PATH-resolved python in v2-models-check

CI failed with `sh: 1: .venv/bin/python: not found`. The recipe
hardcoded `.venv/bin/python`, but `.github/workflows/ci.yml` provisions
Python via `actions/setup-python@v5` + `pip install -e .[dev]` — no
`.venv/` is created on the runner. `just v2-models-check` is the only
recipe CI invokes, so the rest of the justfile is left untouched (those
recipes are dev-only and devs run them with `.venv` on PATH anyway).

Verified: `just v2-models-check` passes locally on the devcontainer
(`.venv/bin` on PATH → `python` resolves to the venv) and will resolve
to the runner's setup-python interpreter on CI.

Author: caviri

justfile

@@ -164,9 +164,13 @@ test-offline:
 v2-models-generate:
     PYTHONPATH=. .venv/bin/python scripts/v2/generate_v2_models.py
 
-# Check committed v2 generated models are in sync with strict schemas
+# Check committed v2 generated models are in sync with strict schemas.
+# Uses `python` (PATH-resolved) so the recipe works in CI — where
+# `setup-python` installs into the runner env, no `.venv/` — as well as
+# in the devcontainer where `.venv/bin` is on PATH after activation. CI
+# invokes this recipe via `just v2-models-check`.
 v2-models-check:
-    PYTHONPATH=. .venv/bin/python scripts/v2/generate_v2_models.py --check
+    PYTHONPATH=. python scripts/v2/generate_v2_models.py --check
 
 # Run LLM repository agent end-to-end with real GIMIE context (no server needed)
 # Usage: just v2-run-repo-agent sdsc-ordes/gimie