feat: compare plan sheets 001/002 to locate ground-level texts

Shows CR-TABL-TEX2 carries the same positions with different decimal values
between sheets (e.g. 63.938 vs 65.969), consistent with differing ground
levels. Interpretation of the 740.00~980.00 ruler is left to HITL.

Co-Authored-By: Claude Haiku 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01A5Cun3RHQKna9qxE6ybZ4A

scripts/compare_plan_sheets.py

@@ -0,0 +1,34 @@
+#!/usr/bin/env python3
+"""Compare two plan sheets layer-by-layer and list elevation-like numeric
+texts (decimal values in 0..1000) per layer, to locate ground levels (지반고).
+Read-only on the source DXF."""
+import collections
+import re
+import sys
+
+import ezdxf
+
+num = re.compile(r"^-?\d{1,4}\.\d{1,3}$")
+
+
+def scan(path):
+    msp = ezdxf.readfile(path).modelspace()
+    layers = collections.Counter(e.dxf.layer for e in msp)
+    el = collections.defaultdict(list)
+    for e in msp.query("TEXT"):
+        s = e.dxf.text.strip()
+        if num.match(s) and 0 <= float(s) <= 1000:
+            el[e.dxf.layer].append((round(e.dxf.insert.x, 1), round(e.dxf.insert.y, 1), s))
+    return layers, el
+
+la, ea = scan(sys.argv[1])
+lb, eb = scan(sys.argv[2])
+print("layers only in 001:", sorted(set(la) - set(lb)))
+print("layers only in 002:", sorted(set(lb) - set(la)))
+for lay in sorted(set(la) | set(lb)):
+    if la[lay] != lb[lay]:
+        print(f"  count diff {lay}: 001={la[lay]} 002={lb[lay]}")
+print("== elevation-like numeric texts (layer: n, sample)")
+for name, el in (("001", ea), ("002", eb)):
+    for lay, items in sorted(el.items(), key=lambda kv: -len(kv[1])):
+        print(f"  {name} {lay}: n={len(items)} sample={sorted(items)[:6]}")