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>

package.json

@@ -10,7 +10,8 @@
     "preview": "vite preview",
     "test": "vitest run",
     "test:watch": "vitest",
-    "test:coverage": "vitest run --coverage"
+    "test:coverage": "vitest run --coverage",
+    "check:tokens": "node scripts/check-tokens.js"
   },
   "dependencies": {
     "@dnd-kit/core": "^6.3.1",