feat: premium redesign — DM Serif, refined palette, flat score badges

- Design tokens (ds.ts, theme.ts, scoreTheme.ts): new warm palette
  (#152642 navy, #f9f8f6 warm white, #e8e7e4 borders, #b8975a gold accent),
  flat score tier badges replacing CSS gradients, Inter + DM Serif Display typography
- Card components: white-background cards, DM Serif score numbers, max-2 badge
  chips with +N overflow tooltip, editorial score badge positioning
- Layout shell: gold left-accent nav active state, 64px top bar, outlined
  workspace chip, DM Serif page titles
- Shared atoms: GenericBadge (outlined/solid variants), ResultFilterBar
  (simplified chip styles), DecisionContextPanel (dot metrics, no left accent)
- Global replacement (118 files): #1e3a5f→#152642, #e2e8f0→#e8e7e4,
  #f4f6f9→#f9f8f6 — all handled via Node.js for proper UTF-8 safety

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/components/demand/AISearchSavePreview.tsx

@@ -48,7 +48,7 @@ export function AISearchSavePreview({
       <Box sx={{
         maxWidth: 720, mx: 'auto', mt: 2,
         p: 1.5, borderRadius: 1.5, border: '1px solid',
-        borderColor: isAnonymous ? '#7c3aed' : '#e2e8f0',
+        borderColor: isAnonymous ? '#7c3aed' : '#e8e7e4',
         bgcolor: isAnonymous ? '#f5f3ff' : '#f8fafc',
         transition: 'all 0.15s',
       }}>
@@ -86,7 +86,7 @@ export function AISearchSavePreview({
           onClick={onSave}
           disabled={isSaving}
           endIcon={isSaving ? <CircularProgress size={16} color="inherit" /> : <Save size={16} />}
-          sx={{ bgcolor: '#1e3a5f', '&:hover': { bgcolor: '#162d4a' }, textTransform: 'none' }}
+          sx={{ bgcolor: '#152642', '&:hover': { bgcolor: '#162d4a' }, textTransform: 'none' }}
         >
           {isSaving
             ? 'Wird gespeichert…'