Add account settings edit UI and GnuMICR.otf font

- Add gear button in header to open account settings modal
- Modal covers Organization, Bank, Account, Logo upload, and Printer Offset fields
- PUT /api/account/:id backend endpoint with full field validation
- Logo file reader with inline preview; only updates logo if a new file is chosen
- CSS for btn-header-icon, settings-section-label, logo-preview, form-row-4
- Add GnuMICR.otf (tracked alongside existing GnuMICR.ttf)

public/css/style.css

@@ -53,6 +53,17 @@ header {
   cursor: pointer;
 }
 .account-switcher option { background: var(--header-bg); color: #fff; }
+.btn-header-icon {
+  background: rgba(255,255,255,0.15);
+  border: 1px solid rgba(255,255,255,0.3);
+  color: #fff;
+  border-radius: 4px;
+  padding: 2px 7px;
+  font-size: 14px;
+  cursor: pointer;
+  line-height: 1.4;
+}
+.btn-header-icon:hover { background: rgba(255,255,255,0.28); }
 
 /* ── Toolbar ── */
 .toolbar {
@@ -492,8 +503,35 @@ input[type="file"] {
 .wizard-footer .btn-ghost { margin-right: auto; font-size: 12px; }
 
 .form-row-3 { grid-template-columns: 1fr 80px 100px; }
+.form-row-4 { grid-template-columns: repeat(4, 1fr); }
 .field-hint {
   font-size: 11px;
   color: var(--text-muted);
   margin-top: 2px;
 }
+
+/* ── Account settings modal ── */
+.settings-section-label {
+  font-size: 10px;
+  font-weight: 700;
+  text-transform: uppercase;
+  letter-spacing: 0.06em;
+  color: var(--text-muted);
+  padding-bottom: 4px;
+  border-bottom: 1px solid var(--border);
+  margin-top: 4px;
+}
+.logo-preview {
+  margin-top: 6px;
+}
+.logo-preview img {
+  max-height: 60px;
+  max-width: 200px;
+  border: 1px solid var(--border);
+  border-radius: 3px;
+  padding: 3px;
+}
+#acct-settings-modal .modal-body {
+  max-height: calc(100vh - 160px);
+  overflow-y: auto;
+}