Fix: Ubercoin balance display and refresh issues

- Profile page: Add cache: 'no-store' to always fetch fresh balance data
- Profile page: Update balance immediately after tip using transaction result
  to avoid race conditions where DB hasn't committed yet
- Profile page: Reload profile after 500ms delay for data consistency
- UbercoinTipModal: Clarify "Your balance" to avoid confusion with recipient's

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

frontend/src/lib/components/UbercoinTipModal.svelte

@@ -407,7 +407,7 @@
 
             <div class="balance-row">
                 <span class="coin-icon">Ü</span>
-                <span>Balance: <strong>{formatUbercoin($ubercoinBalance)}</strong></span>
+                <span>Your balance: <strong>{formatUbercoin($ubercoinBalance)}</strong></span>
             </div>
 
             <div class="input-group">

frontend/src/routes/profile/[username]/+page.svelte

@@ -32,8 +32,11 @@
     async function loadProfile(username) {
         try {
             // Public endpoint - no auth header needed
-            const response = await fetch(`/api/users/${username}`);
-            
+            // Add cache: 'no-store' to always get fresh data
+            const response = await fetch(`/api/users/${username}`, {
+                cache: 'no-store'
+            });
+
             if (response.ok) {
                 const data = await response.json();
                 profile = data.profile;
@@ -114,11 +117,20 @@
         showTipModal = false;
     }
 
-    function handleTipSent(event) {
+    async function handleTipSent(event) {
         showTipModal = false;
-        // Optionally refresh profile to show updated balance
+        const result = event.detail;
+
+        // Update profile balance immediately based on the transaction result
+        // This avoids race conditions where the DB hasn't committed yet
+        if (profile && result && result.received !== undefined) {
+            profile.ubercoinBalance = (profile.ubercoinBalance || 0) + result.received;
+            profile = profile; // Trigger reactivity
+        }
+
+        // Also reload from server after a short delay to ensure data consistency
         if (profile) {
-            loadProfile(profile.username);
+            setTimeout(() => loadProfile(profile.username), 500);
         }
     }