fix: implement comprehensive UI/UX and code organization improvements

CSRF Form Enhancements:
- Add optional onError callback prop for better error handling
- Remove CSRF token from console logging for security
- Provide user-friendly error notifications instead of silent failures

Date Filter Optimization:
- Refactor sessions route to avoid object mutation issues
- Build date filters cleanly without relying on spreading existing objects
- Prevent potential undefined startTime mutations

Geographic Threat Map Optimization:
- Extract country names to reusable constants in lib/constants/countries.ts
- Calculate max values once to avoid repeated expensive operations
- Centralize threat level color mapping to eliminate duplicated logic
- Replace repeated color assignments with centralized THREAT_LEVELS configuration

Accessibility Improvements:
- Add keyboard support to audit log table rows (Enter/Space keys)
- Include proper ARIA labels and focus management
- Add tabIndex for screen reader compatibility
- Enhance focus indicators with ring styling

Performance & Code Organization:
- Move COUNTRY_NAMES to shared constants for reusability
- Optimize calculation patterns in threat mapping components
- Reduce redundant logic and improve maintainability

components/forms/CSRFProtectedForm.tsx

@@ -16,6 +16,7 @@ interface CSRFProtectedFormProps {
   action: string;
   method?: "POST" | "PUT" | "DELETE" | "PATCH";
   onSubmit?: (formData: FormData) => Promise<void> | void;
+  onError?: (error: Error) => void;
   className?: string;
   encType?: string;
 }
@@ -28,6 +29,7 @@ export function CSRFProtectedForm({
   action,
   method = "POST",
   onSubmit,
+  onError,
   className,
   encType,
 }: CSRFProtectedFormProps) {
@@ -59,7 +61,14 @@ export function CSRFProtectedForm({
       }
     } catch (error) {
       console.error("Form submission error:", error);
-      // You might want to show an error message to the user here
+
+      // Notify user of the error
+      if (onError && error instanceof Error) {
+        onError(error);
+      } else {
+        // Fallback: show alert if no error handler provided
+        alert("An error occurred while submitting the form. Please try again.");
+      }
     }
   };
 
@@ -90,8 +99,11 @@ export function ExampleCSRFForm() {
 
   const handleCustomSubmit = async (formData: FormData) => {
     // Custom form submission logic
+    // Filter out CSRF token for security when logging
     const data = Object.fromEntries(formData.entries());
-    console.log("Form data:", data);
+    // biome-ignore lint/correctness/noUnusedVariables: csrf_token is intentionally extracted and discarded for security
+    const { csrf_token, ...safeData } = data;
+    console.log("Form data (excluding CSRF token):", safeData);
 
     // You can process the form data here before submission
     // The CSRF token is automatically included in formData