fix: canonicalize score brackets and assessments

scoring/policy.py

@@ -0,0 +1,35 @@
+"""Canonical score version, brackets, and assessment semantics."""
+
+SCORE_VERSION = "accumulation-score-v2"
+
+# Half-open intervals [low, high), except the final bracket includes 100.
+# Keep labels canonical because they are persisted in live and backtest output.
+SCORE_BRACKETS = [
+    (0, 20, "EXTREME CAUTION"),
+    (20, 35, "CAUTION — OVERHEATED"),
+    (35, 50, "NEUTRAL"),
+    (50, 65, "MODERATE OPPORTUNITY"),
+    (65, 80, "STRONG ACCUMULATION ZONE"),
+    (80, 100, "EXTREME ACCUMULATION ZONE"),
+]
+
+
+def score_in_bracket(score, bracket):
+    """Return whether a 0-100 score belongs to a canonical bracket."""
+    low, high, _ = bracket
+    if not 0 <= score <= 100:
+        return False
+    return low <= score < high or (high == 100 and score == 100)
+
+
+def bracket_for_score(score):
+    """Return the one canonical bracket for a 0-100 score."""
+    for bracket in SCORE_BRACKETS:
+        if score_in_bracket(score, bracket):
+            return bracket
+    raise ValueError(f"score must be between 0 and 100, got {score!r}")
+
+
+def assessment_for_score(score):
+    """Return the canonical assessment label for a score."""
+    return bracket_for_score(score)[2]