feat(model-grounded-detection): group 1, subtract the noise architecture

99 source modules -> 81. 832 tests -> 646. The whole learning/ package (16
modules, ~4,100 lines) and six semantic/ modules removed, with the three gates
byte-identical to 2026-09-06-gate-baseline.txt at every step.

The sequence is what made it safe: vocabularies ported first (1.1), importers
detached second (1.2-1.3), deletion third (1.4). Every import break during the
deletion was therefore a detachment miss in the importer and was fixed there --
no module was restored to satisfy one. Both misses were the same shape and were
fixed as a class: operations.py and shapes.py each imported trailing_name from
the deleted variants.py, so it moved to semantic/ir.py, its natural home, and
both importers changed in one edit.

Ported before deleting: the closed guard vocabulary (verbatim, nothing else
holds it) into model/specs.py, which derives TaintSpec and DominanceSpec from
the retained ruleset facts rather than copying them. Re-homed: families ->
model/taxonomy, candidates -> model/candidates, endpoint -> model/endpoint,
plus Region, labeled_family and labeled_spans. labeled_family no longer falls
back to the LLM classifier -- an unlabeled pair is honestly unknown.

Four deviations, each recorded in the spec notes with its reason. improve/
evolve.py and validator.py were stripped, not deleted: each mixes the mechanism
lever (gone) with the deterministic rule-status loop `ousast improve` still
runs, which has no LLM in it; a test now asserts the lever's absence by symbol
so it cannot creep back. The learning CLI group became `model candidates`,
because deleting it outright would have orphaned the retained enumerator by
removing its only entry point. thinking moved from [learning] to [models].

A gap named rather than papered over: no retained sink fact routes by CWE to
path, output_encoding, untrusted_destination or prototype -- the same hole the
entailment ceiling diagnosed. The test asserts the seeded set and the gap set
exactly, so task 4.2 must update it when it authors those sinks.

The audit found exactly one genuine orphan: vectorstore.py, a bakeoff harness
with no production caller and no CLI, alive only through its own test. The five
named subsystems each carry an explicit decision. Manifest committed, with a
test asserting the tree still matches it.

Group 2 (the Joern go/no-go) has not started.

Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>
Claude-Session: https://claude.ai/code/session_01T7XD7x5KonMdmGRkp63EQG

tests/test_candidate_enumeration.py

@@ -16,7 +16,7 @@ import pytest
 sys.path.insert(0, str(Path(__file__).parent))
 from test_obligation_operations import APP  # noqa: E402
 
-from openultrasast.learning.families import load_families  # noqa: E402
+from openultrasast.model.taxonomy import load_families  # noqa: E402
 from openultrasast.semantic.extra import has_semantic_extra  # noqa: E402
 
 INJECTION = (
@@ -33,7 +33,7 @@ INJECTION = (
 
 
 def _region(path: str = "app.py", function: str | None = "run"):  # type: ignore[no-untyped-def]
-    from openultrasast.learning.detectors import Region
+    from openultrasast.model.candidates import Region
 
     return Region(path=path, function=function)
 
@@ -44,7 +44,7 @@ def _write(tmp_path: Path, name: str, text: str) -> Path:
 
 
 def test_a_call_site_candidate_carries_what_the_model_needs_to_judge_it(tmp_path: Path) -> None:
-    from openultrasast.learning.candidates import enumerate_candidates
+    from openultrasast.model.candidates import enumerate_candidates
 
     root = _write(tmp_path, "app.py", INJECTION)
     result = enumerate_candidates(root, _region(), "injection", taxonomy=load_families())
@@ -62,7 +62,7 @@ def test_a_call_site_candidate_carries_what_the_model_needs_to_judge_it(tmp_path
 
 
 def test_the_family_decides_which_kinds_are_candidates() -> None:
-    from openultrasast.learning.candidates import FAMILY_SHAPE
+    from openultrasast.model.candidates import FAMILY_SHAPE
 
     taxonomy = load_families()
     assert set(FAMILY_SHAPE) == {family.id for family in taxonomy.families}, "every family says what carries its bug"
@@ -76,7 +76,7 @@ def test_the_family_decides_which_kinds_are_candidates() -> None:
 @pytest.mark.skipif(not has_semantic_extra(), reason="the guards come from the parsed IR")
 def test_access_control_candidates_are_operations_with_the_guards_in_scope(tmp_path: Path) -> None:
     """An absence bug has no sink. Its candidate is the operation, and what the model needs is what guards it."""
-    from openultrasast.learning.candidates import enumerate_candidates
+    from openultrasast.model.candidates import enumerate_candidates
 
     root = _write(tmp_path, "app.py", APP)
     guarded = enumerate_candidates(root, _region(function="guarded"), "access_control", taxonomy=load_families())
@@ -95,7 +95,7 @@ def test_access_control_candidates_are_operations_with_the_guards_in_scope(tmp_p
 
 
 def test_a_side_the_parser_rejects_yields_no_candidates_and_says_why(tmp_path: Path) -> None:
-    from openultrasast.learning.candidates import enumerate_candidates
+    from openultrasast.model.candidates import enumerate_candidates
 
     root = _write(tmp_path, "app.py", "def broken(:\n    pass\n")
     result = enumerate_candidates(root, _region(function="broken"), "injection", taxonomy=load_families())
@@ -103,7 +103,7 @@ def test_a_side_the_parser_rejects_yields_no_candidates_and_says_why(tmp_path: P
 
 
 def test_a_labeled_function_with_nothing_to_judge_says_no_candidate(tmp_path: Path) -> None:
-    from openultrasast.learning.candidates import enumerate_candidates
+    from openultrasast.model.candidates import enumerate_candidates
 
     root = _write(tmp_path, "app.py", "def empty():\n    return 1\n")
     result = enumerate_candidates(root, _region(function="empty"), "injection", taxonomy=load_families())
@@ -111,7 +111,7 @@ def test_a_labeled_function_with_nothing_to_judge_says_no_candidate(tmp_path: Pa
 
 
 def test_the_bound_is_a_constant_and_the_overflow_is_counted(tmp_path: Path) -> None:
-    from openultrasast.learning.candidates import MAX_CANDIDATES_PER_CALL, enumerate_candidates
+    from openultrasast.model.candidates import MAX_CANDIDATES_PER_CALL, enumerate_candidates
 
     # one call per line, so the arithmetic is the bound and not the fixture
     body = "\n".join(f"    sink_{index}(value)" for index in range(MAX_CANDIDATES_PER_CALL + 5))
@@ -123,7 +123,7 @@ def test_the_bound_is_a_constant_and_the_overflow_is_counted(tmp_path: Path) ->
 
 def test_enumerating_twice_returns_an_identical_sequence(tmp_path: Path) -> None:
     """The batches, and therefore the sequence of model calls, are determined by the input alone (Req 2.4)."""
-    from openultrasast.learning.candidates import enumerate_candidates
+    from openultrasast.model.candidates import enumerate_candidates
 
     root = _write(tmp_path, "app.py", APP)
     taxonomy = load_families()
@@ -139,7 +139,7 @@ def _order(result):  # type: ignore[no-untyped-def]
 
 
 def test_a_region_without_a_function_enumerates_the_whole_file(tmp_path: Path) -> None:
-    from openultrasast.learning.candidates import enumerate_candidates
+    from openultrasast.model.candidates import enumerate_candidates
 
     root = _write(tmp_path, "app.py", APP)
     whole = enumerate_candidates(root, _region(function=None), "injection", taxonomy=load_families())
@@ -150,7 +150,7 @@ def test_a_region_without_a_function_enumerates_the_whole_file(tmp_path: Path) -
 
 @pytest.mark.parametrize("family", ["injection", "path", "deserialization", "untrusted_destination", "config_secrets"])
 def test_every_family_shape_enumerates_something_on_a_file_that_has_it(tmp_path: Path, family: str) -> None:
-    from openultrasast.learning.candidates import enumerate_candidates
+    from openultrasast.model.candidates import enumerate_candidates
 
     root = _write(tmp_path, "app.py", INJECTION)
     result = enumerate_candidates(root, _region(), family, taxonomy=load_families())
@@ -164,7 +164,7 @@ def test_every_family_shape_enumerates_something_on_a_file_that_has_it(tmp_path:
 
 def test_the_ceiling_counts_labeled_functions_with_at_least_one_candidate(tmp_path: Path) -> None:
     from openultrasast.benchmark import ExpectedFinding
-    from openultrasast.learning.candidates import ceiling
+    from openultrasast.model.candidates import ceiling
     from openultrasast.pairs import PairCase
 
     def case(name: str, body: str, *, slice_name: str, family: str) -> PairCase:
@@ -210,7 +210,7 @@ def test_the_ceiling_counts_labeled_functions_with_at_least_one_candidate(tmp_pa
 
 def test_the_ruleset_generator_is_measured_too_so_the_comparison_is_reproducible(tmp_path: Path) -> None:
     """12.1% against 96.6% is why the ruleset is not the generator. A remembered number is not a measurement."""
-    from openultrasast.learning.candidates import ceiling
+    from openultrasast.model.candidates import ceiling
     from openultrasast.pairs import DEFAULT_CATALOG, load_pair_catalog, select_slice, select_vendored
 
     cases = [c for c in select_vendored(select_slice(load_pair_catalog(DEFAULT_CATALOG), "vibe-py")) if not c.unscorable][:6]
@@ -225,12 +225,12 @@ def test_the_command_runs_offline_and_writes_a_stable_artifact(tmp_path: Path, m
 
     for name in ("OPENULTRASAST_HUNTER_CLIENT", "DEEPSEEK_API_KEY", "OPENROUTER_API_KEY"):
         monkeypatch.delenv(name, raising=False)
-    out = tmp_path / "learning"
-    assert main(["learning", "candidates", "--slice", "vibe-py", "--out", str(out)]) == 0
+    out = tmp_path / "model"
+    assert main(["model", "candidates", "--slice", "vibe-py", "--out", str(out)]) == 0
     artifact = out / "candidate-ceiling.json"
     assert artifact.is_file()
     first = artifact.read_bytes()
-    assert main(["learning", "candidates", "--slice", "vibe-py", "--out", str(out)]) == 0
+    assert main(["model", "candidates", "--slice", "vibe-py", "--out", str(out)]) == 0
     assert artifact.read_bytes() == first, "the ceiling is a property of the corpus, not of when it was measured"
     import json