tools/epro2/kicad: Phase-2 lib_symbols — render symbol bodies from SYMBOL docs

Phase 1 emit的 .kicad_sch 里组件位置 + 属性都对，但 lib_symbols 是空
stub —— KiCad 渲染时每个组件显示成红色 "?"。Phase 2 把 SYMBOL 文档
里的 PART + RECT/POLY/CIRCLE/TEXT/PIN primitives 翻成 KiCad lib symbol
块，填到 lib_symbols 里，让 KiCad 显示真正的原理图符号。

新增 tools/epro2/kicad/sym_writer.py:
  write_lib_symbol(symbol_doc) → S-expr list 形如:
    (symbol "facere:<partId>"
      (pin_numbers (hide no))
      (pin_names (offset 1.016))
      (in_bom yes) (on_board yes)
      (property "Reference" "U" ...)
      (property "Value" "<title>" ...)
      (property "Footprint" "" hide)
      (property "Datasheet" "" hide)
      (symbol "<partId>_1_1"
        (rectangle ...)        ← from RECT.dotX1/Y1/dotX2/Y2
        (polyline (pts ...))   ← from POLY.points + closed → fill
        (circle ...)            ← from CIRCLE.center/radius
        (text "..." ...)        ← from TEXT.value/x/y/rotation
        (pin <type> line (at ...) (length ...) (name ...) (number ...))
                                ← from PIN + sibling ATTR ops
      ))

PIN 名字/编号/电气类型解析（这是关键数据探测点）：
  EPRO2 PIN 不直接带 number/name/type 字段；这些信息存为独立 ATTR 操作
  (parentId=<pin_id>, key="Pin Name"/"Pin Number"/"Pin Type")
  Pin Type 取值映射：IN→input, OUT→output, BIDIR→bidirectional,
  POWER_IN→power_in, POWER_OUT→power_out, NC→no_connect, ...
  默认 passive（保守）

sch_writer 集成（lib_symbols 自动填）：
  write_sch_page(doc, project_relations=pr) — 增 pr 可选参数
  内部 _build_lib_symbols(): 收集本 sheet 用到的 partIds → 通过
  ProjectRelations.parts_by_id 解析到 SYMBOL 文档 → write_lib_symbol →
  组装 (lib_symbols ...) 块；同 partId 多 SYMBOL 候选取第一个，去重
  WriteStats 增 lib_symbols_embedded / lib_symbols_missing

CLI 加 --no-lib-symbols 用于回到 Phase-1 行为（占位符调试用）。

ESP-VoCat 重导出验证：9/9 SCH_PAGE 全部 0 lib_miss
  P1_45092758.kicad_sch    wires=187 symbols=138 lib_emb=29
  codec_0b0163fa.kicad_sch wires=190 symbols=112 lib_emb=20
  Interface_b336a7c7.kicad_sch        symbols=95  lib_emb=13
  ...
  P1_408c9f4f.kicad_sch    wires=  6 symbols= 10 lib_emb= 3

测试：6 个新单测覆盖 outer wrapper / pin ATTR pull / 多形状 primitives /
sch_writer 集成路径 / 缺失 lib 计数 / no-pr 回退到 Phase 1。
合计 **39/39 通过**（parser 6 + relations 9 + project_relations 6 +
sexpr 6 + sch_writer 6 + sym_writer 6）。

下一步 Phase 3：footprint library + .kicad_pcb 导出。

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

tools/epro2/kicad/__main__.py

@@ -15,6 +15,7 @@ import re
 import sys
 from pathlib import Path
 
+from ..project_relations import ProjectRelations
 from ..replay import Project, replay_project
 from .sch_writer import write_sch_page
 
@@ -27,7 +28,12 @@ def _safe_filename(s: str) -> str:
     return s or "untitled"
 
 
-def _convert_one(proj: Project, doc_uuid: str, out_dir: Path) -> Path:
+def _convert_one(
+    proj: Project,
+    doc_uuid: str,
+    out_dir: Path,
+    pr: ProjectRelations | None = None,
+) -> Path:
     if doc_uuid not in proj.documents:
         candidates = [u for u in proj.documents if u.startswith(doc_uuid)]
         if len(candidates) != 1:
@@ -37,7 +43,7 @@ def _convert_one(proj: Project, doc_uuid: str, out_dir: Path) -> Path:
     if doc.doc_type != "SCH_PAGE":
         raise SystemExit(f"doc {doc_uuid} is {doc.doc_type!r}, not SCH_PAGE")
 
-    text = write_sch_page(doc)
+    text = write_sch_page(doc, project_relations=pr)
     title = (doc.objects.get("META") or {}).get("title") or doc_uuid[:12]
     out_path = out_dir / f"{_safe_filename(title)}_{doc_uuid[:8]}.kicad_sch"
     out_path.write_text(text, encoding="utf-8")
@@ -45,7 +51,8 @@ def _convert_one(proj: Project, doc_uuid: str, out_dir: Path) -> Path:
     if stats:
         print(
             f"  {out_path.name}: wires={stats.wires} symbols={stats.symbol_placements} "
-            f"text={stats.text} skipped={stats.skipped}"
+            f"text={stats.text} skipped={stats.skipped} "
+            f"lib_emb={stats.lib_symbols_embedded} lib_miss={stats.lib_symbols_missing}"
         )
     return out_path
 
@@ -57,13 +64,19 @@ def main(argv: list[str] | None = None) -> int:
     g.add_argument("--doc", help="SCH_PAGE doc uuid (or unique prefix) to convert")
     g.add_argument("--all-sch", action="store_true", help="convert every SCH_PAGE")
     ap.add_argument("--out", type=Path, default=Path("data/processed/kicad_sch"))
+    ap.add_argument(
+        "--no-lib-symbols",
+        action="store_true",
+        help="skip lib_symbols generation (Phase 1 mode — placements only, red ?)",
+    )
     args = ap.parse_args(argv)
 
     proj = replay_project(args.project_dir)
     args.out.mkdir(parents=True, exist_ok=True)
+    pr = None if args.no_lib_symbols else ProjectRelations.build(proj)
 
     if args.doc:
-        _convert_one(proj, args.doc, args.out)
+        _convert_one(proj, args.doc, args.out, pr=pr)
         return 0
 
     targets = [u for u, d in proj.documents.items() if d.doc_type == "SCH_PAGE"]
@@ -73,7 +86,7 @@ def main(argv: list[str] | None = None) -> int:
     print(f"Converting {len(targets)} SCH_PAGE docs → {args.out}")
     for u in targets:
         try:
-            _convert_one(proj, u, args.out)
+            _convert_one(proj, u, args.out, pr=pr)
         except Exception as e:  # noqa: BLE001
             print(f"  FAIL {u[:12]}: {e}", file=sys.stderr)
     return 0