Accounts tab and page: savings and mortgage balances kept separate from spending and the budget

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

app_dashboard.html

@@ -32,7 +32,7 @@ td.n,th.n{text-align:right;font-variant-numeric:tabular-nums}.scroll{max-height:
 </head>
 <body>
 <main>
-  <nav class="tabs"><a href="/">Statements</a><a href="/budget">Budget</a><a href="/dashboard" class="on" aria-current="page">Dashboard</a></nav>
+  <nav class="tabs"><a href="/">Statements</a><a href="/budget">Budget</a><a href="/dashboard" class="on" aria-current="page">Dashboard</a><a href="/accounts">Accounts</a></nav>
   <div class="row"><h1>Bills Dashboard</h1><span class="mute" id="updated"></span><div class="spacer"></div>
     <label class="mute">Year <select id="year"></select></label></div>
   <div class="kpis" id="kpis"></div>