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/options/templates/options_settings_swap.html

@@ -1,5 +1,5 @@
 <div class="options-settings-section">
-    <p class="options-settings-hint">主账户资金账户：USDT ↔ USDC 现货市价单。</p>
+    <p class="options-settings-hint">主账户资金账户:USDT ↔ USDC 现货市价单.</p>
     <div class="form-row settings-transfer-form options-settings-row">
         <select id="opt-set-swap-dir" aria-label="兑换方向">
             <option value="usdt_to_usdc" selected>USDT → USDC</option>