Reduce dashboard CSS blast radius for scan terminal work

Dashboard.module.css mixed base shell styles with the entire scan terminal surface, making every decision-card or calendar styling pass risky. This extracts the scan terminal layer into its own CSS module and attaches that module root beside the existing dashboard root so global class selectors keep their current behavior.

Constraint: Preserve existing global scan-* class names and visual cascade.

Rejected: Rename scan classes into scoped module keys | too much DOM churn for a behavior-preserving CSS split.

Rejected: Split card/calendar/mobile rules in the same pass | safer to establish the scan-terminal layer first before finer component CSS ownership.

Confidence: high

Scope-risk: moderate

Reversibility: clean

Tested: npm run build

Not-tested: Pixel-level browser comparison across dark and light themes.

frontend/components/dashboard/ScanTerminalDashboard.tsx

@@ -19,6 +19,7 @@ import {
 import styles from "./Dashboard.module.css";
 import detailChromeStyles from "./DetailPanelChrome.module.css";
 import modalChromeStyles from "./ModalChrome.module.css";
+import scanTerminalStyles from "./ScanTerminal.module.css";
 import { DetailPanel as CityDetailPanel } from "@/components/dashboard/DetailPanel";
 import { FutureForecastModal } from "@/components/dashboard/FutureForecastModal";
 import { MapCanvas } from "@/components/dashboard/MapCanvas";
@@ -372,7 +373,7 @@ function ScanTerminalScreen() {
 
   if (store.proAccess.loading) {
     return (
-      <div className={clsx(styles.root, detailChromeStyles.root, modalChromeStyles.root, themeMode === "light" && "light")}>
+      <div className={clsx(styles.root, scanTerminalStyles.root, detailChromeStyles.root, modalChromeStyles.root, themeMode === "light" && "light")}>
         <div className={clsx("scan-terminal", themeMode === "light" && "light")}>
           <main className="scan-data-grid">
             <div className="scan-loading-state">
@@ -392,7 +393,7 @@ function ScanTerminalScreen() {
   }
 
   return (
-    <div className={clsx(styles.root, detailChromeStyles.root, modalChromeStyles.root, themeMode === "light" && "light")}>
+    <div className={clsx(styles.root, scanTerminalStyles.root, detailChromeStyles.root, modalChromeStyles.root, themeMode === "light" && "light")}>
       <div className={clsx("scan-terminal", themeMode === "light" && "light")}>
         <main className="scan-data-grid">
           <div className="scan-topbar">