feat(api): implement rate limiting and SSRF protection across endpoints

- Added rate limiting to `reaction-users`, `search`, and `image-proxy` APIs to prevent abuse.
- Introduced SSRF protection in `image-proxy` to block requests to private IP ranges.
- Enhanced `link-preview` to use `linkedom` for HTML parsing and improved meta tag extraction.
- Refactored authentication checks in various pages to utilize middleware for cleaner code.
- Improved JWT key loading with error handling and security warnings for production.
- Updated `authFetch` utility to handle token refresh more efficiently with deduplication.
- Enhanced rate limiting utility to trust proxy headers from known sources.
- Numerous layout / design changes

src/layouts/Nav.astro

@@ -46,13 +46,13 @@ const currentPath = Astro.url.pathname;
 
 <script src="/scripts/nav-controls.js" defer data-api-url={API_URL}></script>
 
-<nav class="w-full px-4 sm:px-6 py-4 bg-transparent sticky top-0 z-50 backdrop-blur-sm bg-white/80 dark:bg-[#121212]/80 border-b border-neutral-200/50 dark:border-neutral-800/50">
+<nav class="w-full px-4 sm:px-6 py-3 sticky top-0 z-50 backdrop-blur-xl bg-white/75 dark:bg-[#0a0a0a]/75 border-b border-neutral-200/40 dark:border-neutral-800/40 shadow-sm shadow-neutral-900/5 dark:shadow-black/20">
   <div class="max-w-7xl mx-auto">
     <div class="nav-bar-row flex items-center gap-4 justify-between">
       <!-- Logo/Brand -->
       <a 
             href="/" 
-            class="text-xl sm:text-2xl font-semibold header-text whitespace-nowrap hover:opacity-80 transition-opacity">
+            class="text-xl sm:text-2xl font-bold tracking-tight bg-gradient-to-r from-neutral-900 to-neutral-600 dark:from-white dark:to-neutral-400 bg-clip-text text-transparent whitespace-nowrap hover:opacity-80 transition-opacity font-['IBM_Plex_Sans',sans-serif]">
             {metaData.title}
           </a>
 
@@ -76,10 +76,9 @@ const currentPath = Astro.url.pathname;
                 <a
                   href={item.href}
                   class={isActive 
-                    ? "flex items-center gap-0 px-2.5 py-1.5 rounded-md text-xs font-medium transition-all duration-200 text-white" 
-                    : "flex items-center gap-0 px-2.5 py-1.5 rounded-md text-xs font-medium transition-all duration-200 text-neutral-700 dark:text-neutral-300 hover:bg-neutral-100 dark:hover:bg-neutral-800"
+                    ? "flex items-center gap-0.5 px-3 py-1.5 rounded-lg text-[13px] font-semibold transition-all duration-200 text-white bg-neutral-900 dark:bg-white dark:text-neutral-900 shadow-sm font-['IBM_Plex_Sans',sans-serif]" 
+                    : "flex items-center gap-0.5 px-3 py-1.5 rounded-lg text-[13px] font-medium transition-all duration-200 text-neutral-600 dark:text-neutral-400 hover:text-neutral-900 dark:hover:text-white hover:bg-neutral-100 dark:hover:bg-neutral-800/60 font-['IBM_Plex_Sans',sans-serif]"
                   }
-                  style={isActive ? `background: #111827` : undefined}
                   target={isExternal ? "_blank" : undefined}
                   rel={(isExternal || isAuthedPath) ? "external" : undefined}
                   onclick={item.onclick}