Normalize fullwidth punctuation to ASCII across codebase.

Add scripts/normalize_ambiguous_unicode.py; fix corrupted patch_instance_theme_templates.py. Preserves curly quotes in string literals; removes Git homoglyph warnings on .env.example.

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

manual_trading_hub/static/dashboard.css

@@ -1,4 +1,4 @@
-/* 数据看板 — 随中控亮/暗主题，卡片柔光 */
+/* 数据看板 — 随中控亮/暗主题,卡片柔光 */
 body.hub-page-dashboard {
   --dash-card-bg: var(--panel);
   --dash-card-border: var(--border-soft);