docs(architecture): 完成技术验证 S1–S4，确定 FR-M2-05/06 目标值

- spikes/：Word 转 PDF（Gotenberg）、格式识别、原句坐标、DeepSeek 抽取四项验证代码与两版提示词；样本派生产物和 .env 不进 git
- tech-validation.md：完整结论。四项都可行：WPS 字体字符集要修正并改用行高调整过的字体；格式识别不需要 Docling；表格内切句待改进；抽取需第三道依据校验与规则兜底
- architecture.md：§3.5 加预处理与字体包，§3.6 证据校验改为三道，§10 回填结论
- 03 功能需求与 decisions.md（TV1）：召回 ≥ 99%、采纳准确率 ≥ 95%、页码 100%、高亮正文 ≥ 98% / 表格 ≥ 95%

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

spikes/s1-convert/make_fonts.py

@@ -0,0 +1,30 @@
+"""从 Noto CJK SC 克隆出行高接近宋体 / 黑体的字体（OFL 允许修改，改名后仍按 OFL 分发）。
+字形不变，只改垂直度量：ascent + descent = EM 倍数（参数 total），lineGap = 0。
+用法：python -I make_fonts.py <源目录> <输出目录> <total，如 1.0>"""
+import sys, pathlib
+from fontTools.ttLib import TTCollection
+
+src, dst, total = pathlib.Path(sys.argv[1]), pathlib.Path(sys.argv[2]), float(sys.argv[3])
+dst.mkdir(parents=True, exist_ok=True)
+plan = [("NotoSerifCJK-Regular.ttc", "BD Song", "Regular"), ("NotoSerifCJK-Bold.ttc", "BD Song", "Bold"),
+        ("NotoSansCJK-Regular.ttc", "BD Hei", "Regular"), ("NotoSansCJK-Bold.ttc", "BD Hei", "Bold")]
+for fname, family, style in plan:
+    coll = TTCollection(str(src / fname))
+    font = next(f for f in coll.fonts if "SC" in f["name"].getDebugName(1))
+    upm = font["head"].unitsPerEm
+    asc = round(upm * total * 0.86); desc = round(upm * total) - asc   # 与宋体相同的 0.86 / 0.14 比例
+    font["hhea"].ascent, font["hhea"].descent, font["hhea"].lineGap = asc, -desc, 0
+    os2 = font["OS/2"]
+    os2.sTypoAscender, os2.sTypoDescender, os2.sTypoLineGap = asc, -desc, 0
+    os2.usWinAscent, os2.usWinDescent = asc, desc
+    name = font["name"]
+    full = f"{family} {style}" if style != "Regular" else family
+    for rec in list(name.names):
+        if rec.nameID in (1, 3, 4, 6, 16, 17, 21, 22):
+            name.removeNames(nameID=rec.nameID)
+    for nid, val in ((1, family), (2, style), (3, f"{family.replace(' ', '')}-{style};{total}"),
+                     (4, full), (6, f"{family.replace(' ', '')}-{style}")):
+        name.setName(val, nid, 3, 1, 0x409); name.setName(val, nid, 1, 0, 0)
+    out = dst / f"{family.replace(' ', '')}-{style}.otf"
+    font.save(str(out))
+    print(out.name, upm, asc, desc)