Re-parse .kicad_pcb on PCB exam instead of stale layout_graph.

Cached layout_graph still listed stitching via-pads as component pads,
so PE-BOM-011 kept firing after the ingest fix. PCB/placement jobs now
parse the board file and refresh the cache.

periscope/src/backend/services/pcb_pipeline.py

@@ -417,28 +417,32 @@ async def _ensure_graph(ws: PipelineWorkspace, meta, project_id: str) -> DesignG
 
 
 def _load_layout(ws: PipelineWorkspace) -> LayoutGraph | None:
+    """Parse ``uploads/pcb.kicad_pcb`` with the current ingest.
+
+    ``layout_graph.json`` is a cache written by this parser (or schematic
+    ingest). A stale cache still lists footprint vias as pads, so PCB exam
+    always re-reads the board when the file is present.
+    """
+    pcb = ws.local_path("uploads/pcb.kicad_pcb")
     cached = ws.local_path("layout_graph.json")
+    if pcb.is_file():
+        try:
+            from backend.periscopex.parsers_kicad_pcb import parse_kicad_pcb
+
+            layout = parse_kicad_pcb(pcb)
+            cached.write_text(layout.model_dump_json(indent=2) + "\n")
+            ws._upload_file("layout_graph.json")
+            return layout
+        except Exception:
+            logger.exception("kicad_pcb parse failed during PCB review")
     if cached.is_file():
         try:
             return LayoutGraph.model_validate_json(
                 cached.read_text(encoding="utf-8"),
             )
         except Exception:
-            logger.exception("bad layout_graph.json — trying pcb parse")
-
-    pcb = ws.local_path("uploads/pcb.kicad_pcb")
-    if not pcb.is_file():
-        return None
-    try:
-        from backend.periscopex.parsers_kicad_pcb import parse_kicad_pcb
-
-        layout = parse_kicad_pcb(pcb)
-        cached.write_text(layout.model_dump_json(indent=2) + "\n")
-        ws._upload_file("layout_graph.json")
-        return layout
-    except Exception:
-        logger.exception("kicad_pcb parse failed during PCB review")
-        return None
+            logger.exception("bad layout_graph.json")
+    return None
 
 
 def _cancelled(storage: StorageBackend, user_id: str, project_id: str) -> bool:

periscope/src/backend/services/placement_pipeline.py

@@ -204,29 +204,27 @@ async def _ensure_graph(ws: PipelineWorkspace, meta, project_id: str) -> DesignG
 
 
 def _load_layout(ws: PipelineWorkspace) -> LayoutGraph | None:
-    """Reuse layout_graph.json, or parse uploads/pcb.kicad_pcb once."""
+    """Parse the board when present so via/pad classification stays current."""
+    pcb = ws.local_path("uploads/pcb.kicad_pcb")
     cached = ws.local_path("layout_graph.json")
+    if pcb.is_file():
+        try:
+            from backend.periscopex.parsers_kicad_pcb import parse_kicad_pcb
+
+            layout = parse_kicad_pcb(pcb)
+            cached.write_text(layout.model_dump_json(indent=2) + "\n")
+            ws._upload_file("layout_graph.json")
+            return layout
+        except Exception:
+            logger.exception("kicad_pcb parse failed during placement pack")
     if cached.is_file():
         try:
             return LayoutGraph.model_validate_json(
                 cached.read_text(encoding="utf-8"),
             )
         except Exception:
-            logger.exception("bad layout_graph.json — trying pcb parse")
-
-    pcb = ws.local_path("uploads/pcb.kicad_pcb")
-    if not pcb.is_file():
-        return None
-    try:
-        from backend.periscopex.parsers_kicad_pcb import parse_kicad_pcb
-
-        layout = parse_kicad_pcb(pcb)
-        cached.write_text(layout.model_dump_json(indent=2) + "\n")
-        ws._upload_file("layout_graph.json")
-        return layout
-    except Exception:
-        logger.exception("kicad_pcb parse failed during placement pack")
-        return None
+            logger.exception("bad layout_graph.json")
+    return None
 
 
 def _cancelled(storage: StorageBackend, user_id: str, project_id: str) -> bool:

tests/test_pcb_via_not_pad.py

@@ -269,3 +269,43 @@ def test_tht_solder_pads_stay_component_pads(tmp_path: Path):
     g = parse_kicad_pcb(p)
     assert [p.number for p in g.footprints["R1"].pads] == ["1", "2"]
     assert g.vias == []
+
+
+class _Ws:
+    def __init__(self, root: Path):
+        self.root = root
+
+    def local_path(self, rel: str) -> Path:
+        return self.root / rel
+
+    def _upload_file(self, rel: str) -> None:
+        return None
+
+
+def test_pcb_pipeline_reparses_stale_layout_graph(tmp_path: Path):
+    from backend.periscopex.models import LayoutFootprint, LayoutGraph, LayoutPad
+    from backend.services.pcb_pipeline import _load_layout
+
+    uploads = tmp_path / "uploads"
+    uploads.mkdir()
+    pcb = _qfn24_pcb(
+        tmp_path,
+        n_pads=24,
+        stitch_via_pads=[(26, 0.0, 0.0, "GND")],
+    )
+    (uploads / "pcb.kicad_pcb").write_text(pcb.read_text())
+    stale = LayoutGraph(
+        footprints={
+            "U1": LayoutFootprint(
+                reference="U1",
+                footprint="QFN-24",
+                x=0, y=0, layer="F.Cu",
+                pads=[LayoutPad(number=str(i), x=0, y=0, net="GND") for i in range(1, 35)],
+            ),
+        },
+    )
+    (tmp_path / "layout_graph.json").write_text(stale.model_dump_json())
+    layout = _load_layout(_Ws(tmp_path))
+    assert layout is not None
+    assert len(layout.footprints["U1"].pads) == 24
+    assert len(layout.vias) == 1