feat(ml): Settings → Tagging 'Crop proposers' card (#134 step 3)

Exposes the detector config (per-proposer enable + weights + confidence, caps,
dedupe IoU) in Settings → Tagging, backed by MLSettings via /api/ml/settings.
ml_admin adds the detector fields to _EDITABLE + GET payload + validation (conf
0..1, caps >=1, IoU 0..1). New CropProposersCard.vue (mirrors HeadsCard) with
working defaults pre-filled, per-field live-save (no restart — the agent picks
changes up on its next lease), weights-format help, switch-revert on error.
Closes milestone #134: all three proposers are on out-of-the-box and tunable in
the UI. Test: detector defaults GET + patch round-trip + range validation.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01CDgx8bQS5YrGRK76v8HUnM

tests/test_api_ml_admin.py

@@ -52,6 +52,35 @@ async def test_embedder_model_default_settable_and_empty_rejected(client):
     assert bad.status_code == 400
 
 
+@pytest.mark.asyncio
+async def test_detector_settings_defaults_patch_and_validation(client):
+    # #134: crop-proposer config is exposed + editable here (announced to the
+    # agent via the lease). Defaults are all-on with the pinned weights.
+    body = await (await client.get("/api/ml/settings")).get_json()
+    assert body["detector_person_enabled"] is True
+    assert body["detector_anatomy_enabled"] is True
+    assert "yolov11m_aa22" in body["detector_anatomy_weights"]
+    assert body["detector_panel_weights"].endswith("::best.pt")
+    assert body["detector_max_regions"] == 128
+
+    ok = await client.patch("/api/ml/settings", json={
+        "detector_anatomy_enabled": False,
+        "detector_person_conf": 0.5,
+        "detector_max_panels": 4,
+    })
+    assert ok.status_code == 200
+    out = await ok.get_json()
+    assert out["detector_anatomy_enabled"] is False
+    assert out["detector_person_conf"] == 0.5
+    assert out["detector_max_panels"] == 4
+
+    # Out-of-range confidence + non-positive cap are rejected.
+    assert (await client.patch(
+        "/api/ml/settings", json={"detector_panel_conf": 1.5})).status_code == 400
+    assert (await client.patch(
+        "/api/ml/settings", json={"detector_max_regions": 0})).status_code == 400
+
+
 @pytest.mark.asyncio
 async def test_embedder_models_list(client):
     # #1203: the dropdown reads the supported-model list from the server.