feat(pitch-deck): redirect to pitch if valid session on magic link re-click

If an investor clicks the magic link again after already being logged in,
check /api/auth/me first — valid session → redirect to / immediately
instead of showing the 'link already used' error.

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

pitch-deck/app/auth/verify/page.tsx

@@ -21,6 +21,13 @@ function VerifyContent() {
 
     async function verify() {
       try {
+        // If the investor already has a valid session, skip token verification
+        const sessionCheck = await fetch('/api/auth/me')
+        if (sessionCheck.ok) {
+          router.push('/')
+          return
+        }
+
         const res = await fetch('/api/auth/verify', {
           method: 'POST',
           headers: { 'Content-Type': 'application/json' },