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/hub/hub_sso.py

@@ -1,5 +1,5 @@
 """
-实例浏览器 SSO（复用 HUB_BRIDGE_TOKEN）。无 Flask 依赖，供中控 FastAPI 与各实例共用。
+实例浏览器 SSO(复用 HUB_BRIDGE_TOKEN).无 Flask 依赖,供中控 FastAPI 与各实例共用.
 """
 from __future__ import annotations
 
@@ -109,7 +109,7 @@ def verify_hub_sso_token(
 
 
 def mint_hub_embed_bootstrap(exchange_key: str, next_path: str = "/") -> str | None:
-    """iframe 内嵌登录引导 token（短效、单次），供 /hub-embed-auth 写入 SameSite=None Cookie。"""
+    """iframe 内嵌登录引导 token(短效,单次),供 /hub-embed-auth 写入 SameSite=None Cookie."""
     secret = _sso_secret()
     ex = (exchange_key or "").strip().lower()
     if not secret or not ex: