Rename 'mansion tax' to 'higher-value property bands'

Use official Scottish Government terminology instead of media term.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: MaxGhenis

src/components/Dashboard.jsx

@@ -130,7 +130,7 @@ const TOP_RATE_THRESHOLD_DATA = [
 const SECTIONS = [
   { id: "introduction", label: "Introduction" },
   { id: "income-tax-benefits", label: "Income tax and benefits" },
-  { id: "mansion-tax", label: "Mansion tax" },
+  { id: "mansion-tax", label: "Higher-value property bands" },
 ];
 
 // Common table styles
@@ -869,9 +869,9 @@ export default function Dashboard({ selectedPolicies = [] }) {
             }
           }}
         >
-          mansion tax
+          higher-value property bands
         </a>{" "}
-        on high-value properties from April 2028, detailed in the last section.
+        from April 2028, detailed in the last section.
       </p>
       <details
         className="budget-measures-details"
@@ -1126,7 +1126,7 @@ export default function Dashboard({ selectedPolicies = [] }) {
           <span className="expand-icon" style={{ fontSize: "12px" }}>
             ▶
           </span>
-          Mansion tax
+          Higher-value property bands
         </summary>
         <p className="chart-description" style={{ marginTop: "12px" }}>
           The Scottish Budget 2026-27{" "}

src/components/MansionTaxMap.jsx

@@ -358,7 +358,7 @@ export default function MansionTaxMap() {
         <div className="chart-header">
           <div>
             <h3 className="chart-title">
-              Mansion tax: Band H properties by constituency
+              Higher-value property bands: Band H properties by constituency
             </h3>
             <p className="chart-description">
               The Scottish Budget 2026-27 introduced two new council tax bands