fix(admin): resolve workflows.toml path via CWD instead of __file__

In prod the package is installed in a venv, so __file__.parents[4] doesn't
reach the repo root. Use CWD (repo root in both dev and prod via systemd
WorkingDirectory) with REPO_ROOT env var override.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

web/src/padelnomics/admin/pipeline_routes.py

@@ -51,8 +51,10 @@ bp = Blueprint(
 _LANDING_DIR = os.environ.get("LANDING_DIR", "data/landing")
 _SERVING_DUCKDB_PATH = os.environ.get("SERVING_DUCKDB_PATH", "data/analytics.duckdb")
 
-# Repo root: web/src/padelnomics/admin/ → up 4 levels
-_REPO_ROOT = Path(__file__).resolve().parents[4]
+# In prod the package is installed in a venv so __file__.parents[4] won't
+# reach the repo checkout.  WorkingDirectory in the systemd unit is /opt/padelnomics,
+# so CWD is reliable; REPO_ROOT env var overrides for non-standard setups.
+_REPO_ROOT = Path(os.environ.get("REPO_ROOT", ".")).resolve()
 _WORKFLOWS_TOML = _REPO_ROOT / "infra" / "supervisor" / "workflows.toml"
 
 # A "running" row older than this is considered stale/crashed.