Add CSRF token to event delete fetch() call

The delete event functionality uses vanilla fetch() instead of HTMX,
so it wasn't getting the x-csrf-token header that the htmx:configRequest
listener adds. This caused 403 Forbidden on event deletion.

Changes:
- Made getCsrfToken() a global window function so it can be used by
  both HTMX and vanilla fetch() calls
- Added x-csrf-token header to the deleteEvent() fetch request

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

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

src/animaltrack/web/templates/base.py

@@ -105,15 +105,16 @@ def EventSlideOverScript():  # noqa: N802
 
 
 def CsrfHeaderScript():  # noqa: N802
-    """JavaScript to inject CSRF token into HTMX requests.
+    """JavaScript to inject CSRF token into HTMX requests and provide global helper.
 
-    Reads the csrf_token cookie and adds it as x-csrf-token header
+    Provides a global getCsrfToken() function that reads the csrf_token cookie.
-    to all HTMX requests. This is required for POST/PUT/DELETE
+    This function is used both by HTMX (via htmx:configRequest) and by any
-    requests to pass CSRF validation.
+    vanilla fetch() calls that need CSRF protection.
     """
     return Script("""
-        // Read CSRF token from cookie
+        // Global function to read CSRF token from cookie
-        function getCsrfToken() {
+        // Used by HTMX config and available for vanilla fetch() calls
+        window.getCsrfToken = function() {
             var name = 'csrf_token=';
             var cookies = document.cookie.split(';');
             for (var i = 0; i < cookies.length; i++) {
@@ -123,7 +124,7 @@ def CsrfHeaderScript():  # noqa: N802
                 }
             }
             return '';
-        }
+        };
 
         // Configure HTMX to send CSRF token with all requests
         document.body.addEventListener('htmx:configRequest', function(event) {

src/animaltrack/web/templates/event_detail.py

@@ -535,6 +535,7 @@ def delete_script() -> Script:
                     method: 'POST',
                     headers: {
                         'Content-Type': 'application/x-www-form-urlencoded',
+                        'x-csrf-token': getCsrfToken(),
                     },
                     body: 'reason=Deleted via UI'
                 });