refactor: update module docstrings for clarity and consistency

backend/app/services/lead_policy.py

@@ -1,26 +1,33 @@
+"""Policy helpers for lead-agent approval and planning decisions."""
+
 from __future__ import annotations
 
 import hashlib
 from typing import Mapping
 
 CONFIDENCE_THRESHOLD = 80
+MIN_PLANNING_SIGNALS = 2
 
 
 def compute_confidence(rubric_scores: Mapping[str, int]) -> int:
+    """Compute aggregate confidence from rubric score components."""
     return int(sum(rubric_scores.values()))
 
 
 def approval_required(*, confidence: int, is_external: bool, is_risky: bool) -> bool:
+    """Return whether an action must go through explicit approval."""
     return is_external or is_risky or confidence < CONFIDENCE_THRESHOLD
 
 
 def infer_planning(signals: Mapping[str, bool]) -> bool:
+    """Infer planning intent from boolean heuristic signals."""
     # Require at least two planning signals to avoid spam on general boards.
     truthy = [key for key, value in signals.items() if value]
-    return len(truthy) >= 2
+    return len(truthy) >= MIN_PLANNING_SIGNALS
 
 
 def task_fingerprint(title: str, description: str | None, board_id: str) -> str:
+    """Build a stable hash key for deduplicating similar board tasks."""
     normalized_title = title.strip().lower()
     normalized_desc = (description or "").strip().lower()
     seed = f"{board_id}::{normalized_title}::{normalized_desc}"