fix: correct tojson|safe usage in templates and update validator

- Remove |safe from |tojson in HTML attributes (x-data) - quotes must
  become " for browsers to parse correctly
- Update LANG-002 and LANG-003 architecture rules to document correct
  |tojson usage patterns:
  - HTML attributes: |tojson (no |safe)
  - Script blocks: |tojson|safe
- Fix validator to warn when |tojson|safe is used in x-data (breaks
  HTML attribute parsing)
- Improve code quality across services, APIs, and tests

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

models/schema/notification.py

@@ -14,7 +14,6 @@ from typing import Any
 
 from pydantic import BaseModel, Field
 
-
 # ============================================================================
 # SHARED RESPONSE SCHEMAS
 # ============================================================================
@@ -134,7 +133,9 @@ class TestNotificationRequest(BaseModel):
 
     template_id: int | None = Field(None, description="Template to use")
     email: str | None = Field(None, description="Override recipient email")
-    notification_type: str = Field(default="test", description="Type of notification to send")
+    notification_type: str = Field(
+        default="test", description="Type of notification to send"
+    )
 
 
 # ============================================================================