feat(hunt): feature table, producers, labels, metric, artifact, the DSPy hunt program, runner and CLI

hunter-learning-loop groups 1-3 (first increment). The feature table is the
contract: one row per touched function with diff, source, semantic and
taxonomy columns, provenance per producer, labels by the benchmark's rule.
Producers read the repository at head only (a planted advisory id and
commit text never reach a feature). The hunt program is a DSPy ReAct loop
over a signature whose inputs are the unmasked columns in a fixed order;
answers outside the closed family list or citing unseen lines score as
unknown. The runner writes records the benchmark scorer reads, resumable
by change, program id and mask, and refuses the held-out pilot unless the
run is a report run. Research extra [hunt] = dspy, pandas; the core
install is unchanged. 43 tests on a scripted model, no network.

Co-Authored-By: Claude Fable 5.1 <[email protected]>

tests/test_hunt_metric.py

@@ -0,0 +1,46 @@
+"""Checks that search scoring follows the benchmark's location rule."""
+
+from types import SimpleNamespace
+
+import pytest
+
+from benchmarks.unseen.score import catches
+from openultrasast.hunt.metric import search_metric, search_outcome
+
+
+@pytest.mark.parametrize("change", [
+    {"family": "injection", "path": "app.py", "function": "handler", "function_lines": [100, 140]},
+    {"family": "path", "path": "other.py", "function": "read", "function_lines": [100, 140]},
+    {"family": "config_secrets", "path": "app.py", "function": "handler", "function_lines": [100, 140]},
+])
+def test_matches_score_catches(change):
+    change = {**change, "kind": "vulnerability", "files": [{"path": "app.py", "head_lines": [[20, 22]]}]}
+    for path in ("app.py", "other.py"):
+        for line in (9, 10, 22, 32, 33, 110, 500):
+            for function in ("handler", "other"):
+                for family in (change["family"], "unknown"):
+                    finding = {"path": path, "line": line, "function": function, "family": family}
+                    record = {**change, "push": {"admission": {"defects": [
+                        {**finding, "locations": [[path, line]]}
+                    ]}}}
+                    assert search_outcome(change, [finding]).hit == bool(catches(record))
+
+
+def test_counts_scope_feedback_and_tolerance():
+    change = {"kind": "vulnerability", "path": "app.py", "function": "handle", "family": "path",
+              "function_lines": [20, 22], "files": [{"path": "app.py", "head_lines": [[20, 22]]}]}
+    findings = [{"path": "app.py", "line": 10, "family": "path"},
+                {"path": "other.py", "line": 30, "family": "path"}]
+    outcome = search_outcome(change, findings)
+    assert (outcome.hit, outcome.suspicions, outcome.on_diff) == (True, 2, 1)
+    assert "other.py:30" in outcome.feedback
+    missed = search_outcome(change, findings, tolerance=0)
+    assert not missed.hit
+    assert "missed app.py:20 handle family path" in missed.feedback
+    assert search_metric({"change": change}, {"findings": findings}) == 1.0
+    assert search_metric(SimpleNamespace(change=change), SimpleNamespace(findings=[])) == 0.0
+
+
+@pytest.mark.parametrize("count,expected", [(0, 1.0), (1, 0.8), (5, 0.0), (7, 0.0)])
+def test_ordinary_metric(count, expected):
+    assert search_metric({"kind": "ordinary", "files": []}, {"findings": [{}] * count}) == expected