feat: explicit + prefix on positive P&L values (CVD accessibility)

Gain/loss no longer rides on green/red alone — red-green color vision
deficiency affects ~8% of males; the minus sign already printed, now the
plus does too.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

api/static/dashboard.html

@@ -690,7 +690,10 @@ const money = (v) => (v === null || v === undefined || isNaN(+v)) ? "—" : (v <
 const esc = (s) => String(s ?? "").replace(/[&<>"']/g, c => ({"&":"&amp;","<":"&lt;",">":"&gt;",'"':"&quot;","'":"&#39;"}[c]));
 const timeOf = (ts) => { try { return new Date(ts).toLocaleTimeString(); } catch { return "—"; } };
 const signed = (el, v) => {
-  el.textContent = (v === null || v === undefined || isNaN(+v)) ? "—" : money(v);
+  // explicit "+" so gain/loss never rides on color alone (red-green CVD ~8% of
+  // males; the minus already prints, the plus must too)
+  el.textContent = (v === null || v === undefined || isNaN(+v)) ? "—"
+    : (+v > 0 ? "+" : "") + money(v);
   el.className = "value num " + (+v > 0 ? "pos" : +v < 0 ? "neg" : "");
 };