fix(clients): stale signature bug, monthly turnover/annual income fields, senior citizen/PWD classification

- Fix signature-document reads picking the oldest upload instead of the latest across 7 call
  sites (CKYC tab, view/delete-signature dialogs, edit-wizard preview, cashier transaction entry,
  signatory service, record-master) by sorting on document id instead of an unsorted find().
- Add Monthly Turnover and Annual Income fields alongside the renamed Yearly Turnover field.
- Add Senior Citizen (auto-detected from DOB) and Person with Disability classification, with a
  required disability-certificate upload gate before client creation can proceed.
- Add Graduate and Diploma as distinct Education Levels, with diploma-specific degree options.

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

src/app/clients/client-stepper/client-general-step/client-general-step.component.scss

@@ -56,6 +56,78 @@ form {
   grid-column: 1 / -1;
 }
 
+.senior-citizen-auto-note {
+  display: flex;
+  align-items: center;
+  gap: 8px;
+  font-size: 12px;
+  color: #1074b9;
+  background: #eff6ff;
+  border: 1px solid #bfdbfe;
+  border-radius: 8px;
+  padding: 8px 12px;
+  margin-bottom: 8px;
+}
+
+.doc-upload-field {
+  display: flex;
+  align-items: center;
+  gap: 8px;
+  margin-bottom: 8px;
+}
+
+.doc-upload-label {
+  display: flex;
+  align-items: center;
+  gap: 8px;
+  flex: 1;
+  padding: 10px 14px;
+  border: 1px dashed #cbd5e1;
+  border-radius: 8px;
+  font-size: 13px;
+  color: #475569;
+  cursor: pointer;
+  transition: border-color 0.15s;
+
+  &:hover {
+    border-color: #1074b9;
+  }
+
+  &.doc-upload-label--missing {
+    border-color: #dc2626;
+    color: #dc2626;
+  }
+}
+
+.doc-upload-req {
+  color: #dc2626;
+  font-weight: 700;
+}
+
+.doc-upload-error {
+  font-size: 11px;
+  color: #dc2626;
+}
+
+.subsection-title {
+  display: flex;
+  align-items: center;
+  gap: 6px;
+  font-size: 12px;
+  font-weight: 600;
+  text-transform: uppercase;
+  letter-spacing: 0.04em;
+  color: #6b7280;
+  margin: 20px 0 4px;
+  padding-top: 16px;
+  border-top: 1px solid #e5e7eb;
+
+  .subsection-icon {
+    color: var(--md-sys-color-primary, #1074b9);
+    font-size: 12px;
+  }
+}
+
 .checkbox-field {
   display: flex;
   align-items: center;
@@ -234,6 +306,18 @@ form {
   letter-spacing: 0.5px;
 }
 
+.senior-citizen-badge {
+  font-size: 10px;
+  font-weight: 700;
+  padding: 2px 8px;
+  border-radius: 10px;
+  background: #eff6ff;
+  color: #1074b9;
+  margin-left: 6px;
+  text-transform: uppercase;
+  letter-spacing: 0.5px;
+}
+
 /* ═══ Guardian Section (Redesigned) ═══ */
 .guardian-section {
   margin-top: 12px;