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/instance_nav_lib.py

@@ -1,4 +1,4 @@
-"""中控 iframe 内软导航：服务端跳过重型同步，避免切 tab 等待数秒。"""
+"""中控 iframe 内软导航:服务端跳过重型同步,避免切 tab 等待数秒."""
 
 from __future__ import annotations
 
@@ -6,7 +6,7 @@ from flask import Request
 
 
 def request_is_hub_soft_nav(req: Request | None = None) -> bool:
-    """embed=1 且带 X-Instance-Soft-Nav 头：实例页内 fetch 换页，非整页刷新。"""
+    """embed=1 且带 X-Instance-Soft-Nav 头:实例页内 fetch 换页,非整页刷新."""
     try:
         from flask import request as flask_request