Track all link clicks (internal + external) in analytics; v1.1.33

Replaces outbound-only tracking with a useLinkClickTracking hook that
captures every <a> click on the site. Stores as link_click events keyed
by destination URL, with an internal flag. Admin analytics page gains a
Link Clicks table sorted by count, showing type (internal/external).

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/AdminPage.tsx

@@ -601,6 +601,7 @@ export interface AdminStats {
     scrollDepth: Array<{ path: string; 25?: number; 50?: number; 75?: number; 90?: number }>
     timeOnPage: Array<{ path: string; avgSeconds: number; count: number }>
     topOutboundClicks: Array<{ url: string; count: number }>
+    topLinkClicks: Array<{ url: string; count: number; internal: boolean }>
     topUTMSources: Array<{ source: string; count: number }>
     topSearchQueries: Array<{ query: string; count: number }>
     top404s: Array<{ path: string; count: number }>