feat(review): 取证层多源化 + 视觉多图（整体+2x2 象限）

- 新增 evidence_model.py：统一证据模型（source_type + images 列表），访问器兼容旧 image_b64/image_mime 单图字段
- phases/evidence.py：新增 collect() 多源分发 seam（仅 CAD）、capture_images() 整体+等分象限多图（结束复位视口）、sub_windows()
- phases/review.py：多图逐张下采样喂 LLM，payload 增加 source_type
- config.py：EVIDENCE_DETAIL_TILES=4 / EVIDENCE_MAX_IMAGES=5（默认开启多图）
- 新增 tests/test_evidence_model.py，更新 evidence/review 断言与 fakes 归一

tests/fakes.py

@@ -10,6 +10,7 @@
 
 import json
 
+from dwg_review import evidence_model
 from dwg_review.cad_tools import CadTools
 from dwg_review.checklist import DEFAULT_CHECKLIST
 from dwg_review.context import ReviewContext
@@ -313,10 +314,23 @@ def make_evidence(
     bbox=(0.0, 0.0, 100.0, 50.0),
     image_b64=None,
     image_mime=None,
+    images=None,
+    source_type=None,
     **over,
 ):
-    """构造 collect_frame 的返回值（evidence）。"""
+    """构造 collect_frame 的返回值（evidence）。
+
+    兼容旧的 `image_b64`/`image_mime` 单图入参：若给了 image_b64 而未给 images，
+    则归一进 `images` 列表（与 `evidence_model.evidence_images` 的归一保持一致）。
+    """
+    if images is None:
+        images = []
+        if image_b64:
+            images.append(
+                evidence_model.make_image(image_b64, image_mime or "image/png")
+            )
     ev = {
+        "source_type": source_type or evidence_model.SOURCE_CAD,
         "index": index,
         "frame": frame(bbox),
         "window": {
@@ -330,8 +344,7 @@ def make_evidence(
         "dimensions": {"total": 0, "items": []},
         "blocks": {"total": 0, "items": []},
         "polylines": {"total": 0, "items": []},
-        "image_b64": image_b64,
-        "image_mime": image_mime,
+        "images": images,
     }
     ev.update(over)
     return ev

tests/test_evidence.py

@@ -55,8 +55,8 @@ def test_collect_frame_assembles_evidence():
     assert ev["dimensions"]["total"] == 2
     assert ev["blocks"]["total"] == 0
     assert ev["polylines"]["total"] == 3
-    assert ev["image_b64"] == "QUJD"
-    assert ev["image_mime"] == "image/png"
+    assert ev["source_type"] == "cad"
+    assert ev["images"] == [{"b64": "QUJD", "mime": "image/png", "label": "overall"}]
 
 
 def test_collect_frame_calls_expected_tools():
@@ -80,12 +80,64 @@ def test_collect_frame_calls_expected_tools():
 def test_collect_frame_without_image():
     ctx = make_ctx(client=build_evidence_client(image=ok_text({})))
     ev = collect_frame(ctx, 1, frame([0, 0, 10, 10]))
-    assert ev["image_b64"] is None
-    assert ev["image_mime"] is None
+    assert ev["images"] == []
 
 
 def test_collect_frame_tolerates_empty_structured_data():
     ctx = make_ctx(client=FakeMcpClient())  # 全部默认 ok_text({})
     ev = collect_frame(ctx, 1, frame([0, 0, 10, 10]))
     assert ev["entities"] == {}
-    assert ev["image_b64"] is None
+    assert ev["images"] == []
+
+
+def test_sub_windows_2x2():
+    from dwg_review.phases.evidence import sub_windows
+
+    win = {"min_x": 0.0, "min_y": 0.0, "max_x": 10.0, "max_y": 10.0}
+    subs = sub_windows(win, 4)
+    assert len(subs) == 4
+    # 行优先：左上 → 右上 → 左下 → 右下
+    assert subs[0] == {"min_x": 0.0, "min_y": 5.0, "max_x": 5.0, "max_y": 10.0}
+    assert subs[1] == {"min_x": 5.0, "min_y": 5.0, "max_x": 10.0, "max_y": 10.0}
+    assert subs[2] == {"min_x": 0.0, "min_y": 0.0, "max_x": 5.0, "max_y": 5.0}
+    assert subs[3] == {"min_x": 5.0, "min_y": 0.0, "max_x": 10.0, "max_y": 5.0}
+
+
+def test_sub_windows_disabled():
+    from dwg_review.phases.evidence import sub_windows
+
+    win = {"min_x": 0.0, "min_y": 0.0, "max_x": 10.0, "max_y": 10.0}
+    assert sub_windows(win, 0) == []
+    assert sub_windows(win, 1) == []
+
+
+def test_collect_frame_captures_multiple_images(monkeypatch):
+    from dwg_review import config
+    from dwg_review.phases.evidence import collect_frame
+
+    monkeypatch.setattr(config, "EVIDENCE_DETAIL_TILES", 4)
+    ctx = make_ctx(client=build_evidence_client())
+    ev = collect_frame(ctx, 1, frame([0, 0, 100, 50]))
+    assert [img["label"] for img in ev["images"]] == [
+        "overall",
+        "tile-1",
+        "tile-2",
+        "tile-3",
+        "tile-4",
+    ]
+
+
+def test_collect_dispatches_cad_source():
+    from dwg_review.phases.evidence import collect
+
+    ctx = make_ctx(client=build_evidence_client())
+    ev = collect(ctx, 1, frame([0, 0, 10, 10]))
+    assert ev is not None
+    assert ev["source_type"] == "cad"
+
+
+def test_collect_returns_none_for_unsupported_source():
+    from dwg_review.phases.evidence import collect
+
+    ctx = make_ctx(client=FakeMcpClient())
+    assert collect(ctx, 1, {"source_type": "pdf", "bbox": [0, 0, 1, 1]}) is None

tests/test_evidence_model.py

@@ -0,0 +1,100 @@
+"""`dwg_review.evidence_model` 单元测试。"""
+
+from dwg_review import evidence_model as em
+
+
+def test_make_image_defaults():
+    assert em.make_image("QUJD") == {"b64": "QUJD", "mime": "image/png", "label": None}
+
+
+def test_make_image_custom():
+    assert em.make_image("QUJD", "image/jpeg", "tile-1") == {
+        "b64": "QUJD",
+        "mime": "image/jpeg",
+        "label": "tile-1",
+    }
+
+
+def test_make_image_empty_mime_falls_back():
+    assert em.make_image("x", "")["mime"] == "image/png"
+
+
+def test_source_type_of_default_cad():
+    assert em.source_type_of({}) == em.SOURCE_CAD
+    assert em.source_type_of(None) == em.SOURCE_CAD
+    assert em.source_type_of({"source_type": ""}) == em.SOURCE_CAD
+
+
+def test_source_type_of_explicit():
+    assert em.source_type_of({"source_type": "pdf"}) == "pdf"
+    assert em.source_type_of({"source_type": "image"}) == "image"
+
+
+def test_evidence_images_new_form():
+    ev = {
+        "images": [
+            em.make_image("A", label="overall"),
+            em.make_image("B", label="tile-1"),
+        ]
+    }
+    out = em.evidence_images(ev)
+    assert [i["b64"] for i in out] == ["A", "B"]
+    assert [i["label"] for i in out] == ["overall", "tile-1"]
+
+
+def test_evidence_images_filters_empty_b64():
+    ev = {"images": [{"b64": "", "mime": "image/png"}, {"b64": "A"}]}
+    out = em.evidence_images(ev)
+    assert len(out) == 1
+    assert out[0]["b64"] == "A"
+
+
+def test_evidence_images_legacy_fallback():
+    ev = {"image_b64": "LEG", "image_mime": "image/jpeg"}
+    assert em.evidence_images(ev) == [
+        {"b64": "LEG", "mime": "image/jpeg", "label": None}
+    ]
+
+
+def test_evidence_images_legacy_default_mime():
+    assert em.evidence_images({"image_b64": "LEG"})[0]["mime"] == "image/png"
+
+
+def test_evidence_images_empty():
+    assert em.evidence_images({}) == []
+    assert em.evidence_images(None) == []
+    assert em.evidence_images({"images": []}) == []
+
+
+def test_evidence_images_prefers_new_over_legacy():
+    ev = {"images": [em.make_image("NEW")], "image_b64": "OLD"}
+    assert [i["b64"] for i in em.evidence_images(ev)] == ["NEW"]
+
+
+def test_primary_image_prefers_overall():
+    ev = {
+        "images": [
+            em.make_image("A", label="tile-1"),
+            em.make_image("B", label="overall"),
+        ]
+    }
+    assert em.primary_image(ev)["b64"] == "B"
+
+
+def test_primary_image_first_when_no_overall():
+    ev = {"images": [em.make_image("A", label="tile-1"), em.make_image("B")]}
+    assert em.primary_image(ev)["b64"] == "A"
+
+
+def test_primary_image_none_when_empty():
+    assert em.primary_image({}) is None
+
+
+def test_image_labels():
+    ev = {
+        "images": [
+            em.make_image("A", label="overall"),
+            em.make_image("B", label="tile-1"),
+        ]
+    }
+    assert em.image_labels(ev) == ["overall", "tile-1"]

tests/test_review.py

@@ -28,8 +28,8 @@ from tests.fakes import (
 def test_evidence_payload_strips_image():
     ev = make_evidence(image_b64="QUJD", image_mime="image/png")
     payload = evidence_payload(ev)
+    assert "images" not in payload
     assert "image_b64" not in payload
-    assert "image_mime" not in payload
     assert payload["frame_index"] == 1
 
 
@@ -243,3 +243,20 @@ def test_review_frame_intermediate_tool_turn_json_not_parsed():
     out = review_frame(ctx, make_evidence(), "sys", log=lambda *a: None)
     assert out["summary"] == "最终结论"
     assert out["issues"] == []
+
+
+def test_review_frame_includes_multiple_image_blocks():
+    llm = FakeLlmClient(script=[llm_text("ok")])
+    ctx = make_ctx(client=FakeMcpClient(), llm=llm)
+    ev = make_evidence(
+        images=[
+            {"b64": "A", "mime": "image/png", "label": "overall"},
+            {"b64": "B", "mime": "image/png", "label": "tile-1"},
+        ]
+    )
+    review_frame(ctx, ev, "sys", log=lambda *a: None)
+    user_content = llm.calls[0]["messages"][1]["content"]
+    image_blocks = [b for b in user_content if b.get("type") == "image_url"]
+    assert len(image_blocks) == 2
+    assert any(b.get("text") == "（截图：overall）" for b in user_content)
+    assert any(b.get("text") == "（截图：tile-1）" for b in user_content)