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>

lib/instance/templates/instance_header_stats.html

@@ -1,4 +1,4 @@
-{# 资金与统计条（顶栏 / 系统设置共用，单行展示） #}
+{# 资金与统计条(顶栏 / 系统设置共用,单行展示) #}
 <div class="instance-header-stats{% if options_enabled %} instance-header-stats--options{% endif %}">
     <div class="stat-strip-item stat-strip-item--primary">
         <div class="label">交易所</div>
@@ -16,7 +16,7 @@
         <div class="label">胜率</div>
         <div class="value" id="stat-rate" data-funds-field="stat-rate">{{ rate }}%</div>
     </div>
-    <div class="stat-strip-item" title="平均盈利 ÷ 平均亏损（当前列表窗口）">
+    <div class="stat-strip-item" title="平均盈利 ÷ 平均亏损(当前列表窗口)">
         <div class="label">盈亏比</div>
         <div class="value" id="stat-pl-ratio" data-funds-field="stat-pl-ratio">{% if profit_loss_ratio is not none %}{{ profit_loss_ratio }}{% else %}—{% endif %}</div>
     </div>