fix: isolate canvas CJK strings and guard build encoding

Co-authored-by: Cursor <cursoragent@cursor.com>

apps/web/scripts/diagnose-topology-encoding.py

@@ -0,0 +1,26 @@
+# -*- coding: utf-8 -*-
+"""Diagnose TopologyCanvas.tsx encoding / CJK corruption."""
+from __future__ import annotations
+
+import re
+from pathlib import Path
+
+p = Path(__file__).resolve().parents[1] / "src" / "TopologyCanvas.tsx"
+raw = p.read_bytes()
+print("size", len(raw))
+print("bom", raw[:3] == b"\xef\xbb\xbf")
+try:
+    text = raw.decode("utf-8")
+    print("utf8: OK")
+except UnicodeDecodeError as e:
+    print("utf8: FAIL", e)
+    print("bad-byte context:", raw[max(0, e.start - 30) : e.start + 30])
+    text = raw.decode("latin1")
+
+quoted = re.findall(r'"\?{2,}"', text)
+print("quoted ?? count:", len(quoted))
+print("cjk chars:", len(re.findall(r"[\u4e00-\u9fff]", text)))
+for i, line in enumerate(text.splitlines(), 1):
+    if '["select"' in line or "title=" in line and "?" in line and "??" in line:
+        if i >= 1180 and i <= 1360:
+            print(f"{i}: {line.strip()[:100]}")