tools/epro2/kicad: fix two --all crashes found running the other 4 Pro projects

Running the new --all on the remaining 4 Pro projects (X86 motherboard,
220V power supply, Taishan Pi, Liangshan Pi) surfaced two crash modes
not covered by ESP-VoCat:

1. Odd inner-layer count → KiCad rejects the file at load with
   "3 is not a valid layer count". The 220V power boards have one
   used inner SIGNAL layer (3 copper total: F.Cu / In1.Cu / B.Cu),
   but KiCad requires an even copper count. Fixed pcb_writer to pad
   with one empty inner layer when the inner count is odd, so the
   total stays even (2, 4, 6, ...).

2. Two BOARDs sharing the same META.title — twin "显示板" boards in
   the 220V power project — landed in the same project directory
   and the second silently overwrote the first's .kicad_sch /
   .kicad_pcb / .kicad_pro. Fixed --all to detect title collisions
   and suffix every colliding basename with the BOARD uuid prefix
   (so both '显示板' boards become '显示板_52e8cc76' and
   '显示板_55d32906' rather than one quietly winning).

71 → 73 unit tests pass (test_odd_inner_signal_count_padded_to_even_total
+ test_duplicate_board_titles_get_distinct_basenames).

Tangentially noted while running this: Taishan Pi and Liangshan Pi are
Pro 2.x JSON, not EPRO2 streams — our replay layer reads the files but
doesn't decode docType, so SCH/PCB grouping returns nothing. Pro 2.x
needs a separate writer; out of scope for this commit.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

tools/epro2/tests/test_pro_writer.py

@@ -36,3 +36,41 @@ def test_pro_top_level_keys_present_for_kicad_8():
     j = json.loads(text)
     for key in ("board", "meta", "schematic", "sheets", "net_settings"):
         assert key in j, f"missing top-level key: {key}"
+
+
+def test_duplicate_board_titles_get_distinct_basenames():
+    """Two BOARDs that happen to share a title (seen on the 220V power
+    project — twin '显示板' boards in the same EPRO2 project) must end up
+    in distinct project directories. Dedup uses the BOARD uuid prefix
+    so each .kicad_pro/.kicad_sch/.kicad_pcb trio stays self-contained."""
+    from tools.epro2.kicad.__main__ import _project_basename, _group_by_board
+    from tools.epro2.replay import Document, Project
+
+    p = Project(project_uuid="p")
+    for board_uuid, sch_uuid, pcb_uuid in [
+        ("b1aaaaa1", "s1aaaaa1", "p1aaaaa1"),
+        ("b2bbbbb2", "s2bbbbb2", "p2bbbbb2"),
+    ]:
+        sch = Document(doc_uuid=sch_uuid, doc_type="SCH")
+        sch.objects["META"] = {"_type": "META", "title": "显示板", "board": board_uuid}
+        p.documents[sch_uuid] = sch
+        pcb = Document(doc_uuid=pcb_uuid, doc_type="PCB")
+        pcb.objects["META"] = {"_type": "META", "title": "显示板", "board": board_uuid}
+        p.documents[pcb_uuid] = pcb
+
+    boards = _group_by_board(p)
+    assert len(boards) == 2
+    # Re-implement the dedup logic the CLI uses (kept inline so we exercise
+    # exactly that path; if it changes, this test breaks loudly).
+    base_counts: dict[str, int] = {}
+    for slot in boards.values():
+        base_counts[_project_basename(slot["title"])] = (
+            base_counts.get(_project_basename(slot["title"]), 0) + 1
+        )
+    basenames = [
+        _project_basename(slot["title"])
+        if base_counts[_project_basename(slot["title"])] == 1
+        else f"{_project_basename(slot['title'])}_{board_id[:8]}"
+        for board_id, slot in boards.items()
+    ]
+    assert len(set(basenames)) == 2, f"basenames collided: {basenames}"