Fix ModuleNotFoundError: inline generate_run_id to avoid policyengine_us_data import

The lazy import from policyengine_us_data.utils.run_id triggers the full
package __init__ chain (which needs policyengine_core), but the orchestrator
runs outside the uv venv. Inline the trivial timestamp logic instead.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: baogorek

modal_app/pipeline.py

@@ -100,9 +100,8 @@ def from_dict(cls, data: dict) -> "RunMetadata":
 
 
 def generate_run_id(version: str, sha: str) -> str:
-    from policyengine_us_data.utils.run_id import generate_run_id as _gen
-
-    return _gen(version, sha)
+    ts = datetime.now(timezone.utc).strftime("%Y%m%d_%H%M%S")
+    return f"{version}_{sha[:8]}_{ts}"
 
 
 def write_run_meta(