feat: design token system — DS_TEXT/DS_SURFACE/DS_BORDER + 237 hex migrations

Token infrastructure (src/lib/ds.ts):
- DS_TEXT: 16 semantic text color tokens (primary/secondary/muted/success/
  warning/error/info/brand/signal + dark variants successDark/warningDark/
  signalDark/infoDark for text on tinted surfaces)
- DS_BG: page/surface/subtle/muted background tokens
- DS_BORDER: default/muted/strong border tokens
- DS_SURFACE: 10 bg+border surface pairs (success/warning/error/info/indigo/
  purple/orange/blue/neutral/slate)
- DS_MATCH_TIER: score-tier surface aliases keyed by strong/moderate/weak
- DS_PRE_MARKET / DS_MARKET_SIGNAL: named aliases for futureCard tokens
- DS_SHADOW: card/panel/dialog elevation tokens
- BADGE_COLORS: 14 semantic presets for GenericBadge (confidenceHigh,
  riskMedium, preMarket, marketSignal, verified, gold, silver, bronze…)

GenericBadge (src/components/shared/GenericBadge.tsx):
- New semanticVariant prop (keyof BADGE_COLORS) — preferred over raw hex
- color prop becomes optional (fallback), type-documented as escape hatch

Priority file migrations — 237 hex literals replaced across 10 files:
  ScoreBreakdownPanel.tsx    −22  PipelineDetailPanel.tsx    −22
  FutureAvailabilityCard.tsx −26  AICompareSummary.tsx       −27
  LocationIntelligencePanel  −39  AssistantPromptSuggestions −18
  UnitStructurePanel.tsx     −25  BerichtDialog.tsx          −24
  PreMarketPanel.tsx         −24  PropertyActivityLogPanel   −10

ESLint (eslint.config.js):
- Updated rule message to reference new tokens (DS_TEXT, DS_SURFACE, etc.)
- Added 'stroke' to monitored property names
- Remains 'warn' for gradual migration; use check:tokens for CI gate

CI script (scripts/check-tokens.js + npm run check:tokens):
- Counts hex patterns in components/ + pages/
- Fails if count > THRESHOLD (ratchet: 1958 baseline, lower per sprint)
- Reports top 15 offenders for prioritizing next migration batch

Results: ESLint targeted sx-prop violations: 1752 → 1030 (−41%)
0 TypeScript errors, 154 tests green

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

src/components/assistant/AssistantPromptSuggestions.tsx

@@ -1,5 +1,6 @@
 import { Box, Chip, Typography } from '@mui/material'
 import type { SuggestedQuestion } from '../../domain/assistant'
+import { DS_TEXT, DS_BORDER, DS_SURFACE, BADGE_COLORS } from '../../lib/ds'
 
 interface Props {
   suggestions: SuggestedQuestion[]
@@ -9,26 +10,26 @@ interface Props {
 
 const CATEGORY_COLORS: Record<string, string> = {
   Match: '#4f46e5',
-  Datenqualität: '#d97706',
-  Priorisierung: '#1e3a5f',
-  Empfehlung: '#1a7a4a',
-  Risiko: '#c0392b',
+  Datenqualität: DS_TEXT.warning,
+  Priorisierung: DS_TEXT.brand,
+  Empfehlung: DS_TEXT.success,
+  Risiko: DS_TEXT.error,
   Tradeoffs: '#ea580c',
   Strategie: '#0891b2',
-  Analyse: '#7c3aed',
+  Analyse: BADGE_COLORS.preMarket,
   Erklärung: '#0891b2',
-  Evidenz: '#64748b',
-  Review: '#7c3aed',
-  Konfidenz: '#d97706',
-  Fehler: '#c0392b',
+  Evidenz: DS_TEXT.muted,
+  Review: BADGE_COLORS.preMarket,
+  Konfidenz: DS_TEXT.warning,
+  Fehler: DS_TEXT.error,
   Fehleranalyse: '#ea580c',
   Eskalation: '#ea580c',
-  Prozess: '#64748b',
-  Kosten: '#1a7a4a',
-  Impact: '#d97706',
-  Optimierung: '#1a7a4a',
-  Aktion: '#1e3a5f',
-  Überblick: '#64748b',
+  Prozess: DS_TEXT.muted,
+  Kosten: DS_TEXT.success,
+  Impact: DS_TEXT.warning,
+  Optimierung: DS_TEXT.success,
+  Aktion: DS_TEXT.brand,
+  Überblick: DS_TEXT.muted,
   Ranking: '#4f46e5',
 }
 
@@ -37,12 +38,12 @@ export function AssistantPromptSuggestions({ suggestions, onSelect, disabled }:
 
   return (
     <Box sx={{ px: 2, py: 1.25 }}>
-      <Typography variant="caption" sx={{ fontWeight: 700, textTransform: 'uppercase', letterSpacing: 0.5, color: '#94a3b8', display: 'block', mb: 0.75, fontSize: '0.65rem' }}>
+      <Typography variant="caption" sx={{ fontWeight: 700, textTransform: 'uppercase', letterSpacing: 0.5, color: DS_TEXT.disabled, display: 'block', mb: 0.75, fontSize: '0.65rem' }}>
         Vorschläge
       </Typography>
       <Box sx={{ display: 'flex', flexDirection: 'column', gap: 0.625 }}>
         {suggestions.map(s => {
-          const catColor = CATEGORY_COLORS[s.category] ?? '#64748b'
+          const catColor = CATEGORY_COLORS[s.category] ?? DS_TEXT.muted
           return (
             <Box
               key={s.id}
@@ -51,11 +52,11 @@ export function AssistantPromptSuggestions({ suggestions, onSelect, disabled }:
                 px: 1.25,
                 py: 0.875,
                 borderRadius: 1.5,
-                border: '1px solid #e2e8f0',
+                border: `1px solid ${DS_BORDER.default}`,
                 cursor: disabled ? 'default' : 'pointer',
                 bgcolor: 'white',
                 opacity: disabled ? 0.5 : 1,
-                '&:hover': disabled ? {} : { bgcolor: '#f8fafc', borderColor: '#cbd5e1' },
+                '&:hover': disabled ? {} : { bgcolor: DS_SURFACE.neutral.bg, borderColor: DS_BORDER.strong },
                 transition: 'all 0.1s ease',
                 display: 'flex',
                 alignItems: 'center',