feat!: track MLflow in SQLite and harden the canonical gate

.env.example

@@ -0,0 +1,8 @@
+# Copy to `.env`; `mise.toml` sources it, so every task and hook sees these values.
+
+# MLflow tracking and model registry. SQLite is the local default written by
+# `MlflowService`: runs and registered models live in `mlflow.db`, artifact files under
+# `./mlruns`. Point these at a real database (PostgreSQL, MySQL) or a tracking server
+# (http://127.0.0.1:5000) to share runs across a team — the client code does not change.
+MLFLOW_TRACKING_URI=sqlite:///mlflow.db
+MLFLOW_REGISTRY_URI=sqlite:///mlflow.db