Simplify TransactionsPage header to 'Transaction History'

Removed redundant subtitle and simplified header to just "Transaction History" for cleaner, more concise UI.

Before:
- Title: "My Transactions"
- Subtitle: "View your recent transaction history"

After:
- Title: "Transaction History"
- No subtitle

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

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

src/modules/expenses/views/TransactionsPage.vue

@@ -184,10 +184,7 @@ onMounted(() => {
     <div class="flex flex-col gap-3 p-4 md:p-6 border-b md:bg-card/50 md:backdrop-blur-sm">
       <div class="w-full max-w-3xl mx-auto">
         <div class="flex items-center justify-between mb-3">
-          <div>
-            <h1 class="text-lg md:text-xl font-bold">My Transactions</h1>
-            <p class="text-xs md:text-sm text-muted-foreground">View your recent transaction history</p>
-          </div>
+          <h1 class="text-lg md:text-xl font-bold">Transaction History</h1>
           <Button
             variant="outline"
             size="sm"