Add tools/epro2 — EPRO2 parser + replay prototype

为 Pro 3.x .epro2 工程源数据写解析骨架，下游做 EPRO2→KiCad 转换器
前的基础设施。在 ESP-VoCat (278 docs / 7.5 MB) + 220V 桌面电源
(771 docs / 26 MB) 端到端跑通，0 parse errors。

模块结构：
  tools/epro2/parser.py    单行 → Op：rstrip("|") + split("||") + json.loads
  tools/epro2/replay.py    state-machine：DOCHEAD 设头；其它 op 按 id 做
                           upsert（payload=None 当 delete）；EDIT_HEAD/
                           META/CANVAS/PREFERENCE/PANELIZE 当 doc 级单
                           例存
  tools/epro2/__main__.py  CLI：传项目目录走 manifest.json 重放每个 doc，
                           按 docType 聚合输出 + 可选 --dump-doc 看单文
                           档详情
  tools/epro2/tests/       6 个单测 pin 死 trailing-pipe / 三段消息 /
                           id-only-no-payload / 嵌入管道符等坑

ESP-VoCat 输出示例：
  Documents: 278  (parse_errors=0)
   count  docType         objects        ops  deletes  untyped_ops
     105  SYMBOL             4124       4439        0            0
      88  DEVICE               88        264        0            0
      55  FOOTPRINT          4641       4855        0            0
       9  SCH_PAGE           7982       8167       42            0
       6  PCB                8428       8547       38            0
       6  BOARD                 9         18        0            0
       6  SCH                   9         26        0            0
       1  BLOB                  4          8        0            0
       1  FONT                 16         28        0            0
       1  CONFIG                2          3        0            0
  Top ops: ATTR 7035 / ELE_PLACEHOLDER 4225 / LINE 3005 / LAYER 2318 ...

PCB 文档单 dump 验证语义正确：META 含 title (PCB-EchoEar-CoreBoard-V1_0)
+ board 引用；CANVAS 含 origin/grid/unit (mm)；LAYER 1/2/3 = TOP/BOTTOM/
TOP_SILK 配色齐全。

跑法：
  uv run python -m tools.epro2 data/raw/oshwhub/<project_uuid>
  uv run python -m tools.epro2 data/raw/oshwhub/<uuid> --dump-doc <doc_uuid>

下一步（不在本 commit）：
1. 把对象间关系建起来（COMPONENT.partId → PART；LINE.lineGroup → WIRE；
   PAD_NET id → PAD + NET 三方关联）—— 当前 replay 只做扁平 dict
2. EPRO2 → KiCad 序列化层（Forge 投影硬门槛）
3. 在 Pro 3.x 三个项目做整体回归（X86 主板 7374 docs 可作压力测试）

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

tools/epro2/tests/test_parser.py

@@ -0,0 +1,56 @@
+"""Parser regression tests — pin down the ``rstrip("|")`` invariant that took
+us two debugging rounds to find (see docs/sources/easyeda_pro_source.md §3.1).
+"""
+
+from tools.epro2.parser import parse_line, Epro2ParseError
+
+
+def test_dochead_with_trailing_pipe():
+    ln = b'{"type":"DOCHEAD","ticket":2}||{"docType":"BOARD","uuid":"35086b7d90787675","editVersion":"3.2.127"}|'
+    op = parse_line(ln)
+    assert op.type == "DOCHEAD"
+    assert op.ticket == 2
+    assert op.payload["docType"] == "BOARD"
+    assert op.payload["uuid"] == "35086b7d90787675"
+    assert op.payload["editVersion"] == "3.2.127"
+
+
+def test_three_part_message():
+    """Some types carry an `extra` third field after the second `||`."""
+    ln = b'{"type":"WIRE","ticket":1009,"id":"e3514"}||{"groupId":""}||{"meta":1}|'
+    op = parse_line(ln)
+    assert op.type == "WIRE"
+    assert op.id == "e3514"
+    assert op.payload == {"groupId": ""}
+    assert op.extra == {"meta": 1}
+
+
+def test_id_only_no_payload_yields_none_payload():
+    ln = b'{"type":"COMPONENT","ticket":7,"id":"e1"}|'
+    op = parse_line(ln)
+    assert op.type == "COMPONENT"
+    assert op.id == "e1"
+    assert op.payload is None  # downstream replay treats this as a delete
+
+
+def test_bad_head_raises():
+    try:
+        parse_line(b"not json||{}|")
+    except Epro2ParseError:
+        return
+    raise AssertionError("expected Epro2ParseError")
+
+
+def test_empty_line_raises():
+    try:
+        parse_line(b"|")
+    except Epro2ParseError:
+        return
+    raise AssertionError("expected Epro2ParseError")
+
+
+def test_payload_with_embedded_pipes():
+    """An embedded `|` inside a JSON string must NOT be treated as a separator."""
+    ln = b'{"type":"ATTR","ticket":3,"id":"e1"}||{"key":"Symbol","value":"a|b|c"}|'
+    op = parse_line(ln)
+    assert op.payload["value"] == "a|b|c"