feat: add Relay Setup 101 article link to PWA settings

- Added third relay education article link in PWA settings
- Links to /a/naddr1qvzqqqr4gupzq3svyhng9ld8sv44950j957j9vchdktj7cxumsep9mvvjthc2pjuqq9hyetvv9uj6um9w36hq9mgjg8
- Updated punctuation to use commas for better readability (here, here, and here)

src/components/Settings/PWASettings.tsx

@@ -151,7 +151,7 @@ const PWASettings: React.FC<PWASettingsProps> = ({ settings, onUpdate, onClose }
               >
                 here
               </a>
-              {' and '}
+              {', '}
               <a 
                 onClick={(e) => {
                   e.preventDefault()
@@ -161,6 +161,16 @@ const PWASettings: React.FC<PWASettingsProps> = ({ settings, onUpdate, onClose }
               >
                 here
               </a>
+              {', and '}
+              <a 
+                onClick={(e) => {
+                  e.preventDefault()
+                  handleLinkClick('/a/naddr1qvzqqqr4gupzq3svyhng9ld8sv44950j957j9vchdktj7cxumsep9mvvjthc2pjuqq9hyetvv9uj6um9w36hq9mgjg8')
+                }}
+                style={{ color: 'var(--accent, #8b5cf6)', cursor: 'pointer' }}
+              >
+                here
+              </a>
               .
             </p>
           </div>