UI/UX redesign: unified refined-glass design system

- Add shared UI primitives: Button, Field/Input/Select, PageHeader,
  Section, Callout, Tabs, Disclosure
- Replace gradient buttons with single blue-accent btn-primary
- Reserve gradient text for the brand wordmark only
- Rework Scanner page onto the glass system; collapse explainer and
  glossary into a disclosure, move filters into a glass toolbar
- Restructure Ticker Detail into tabs (Analysis / Indicators / S/R)
  with chart and recommendation always visible
- Align Watchlist, Rankings, Admin, Login/Register to shared primitives
- Unify stray indigo/violet/gray accents into the blue family

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

frontend/src/components/scanner/TradeTable.tsx

@@ -104,7 +104,7 @@ export function TradeTable({ trades, sortColumn, sortDirection, onSort }: TradeT
                 </td>
                 <td className="px-4 py-3.5">
                   <div className="space-y-0.5">
-                    <span className="text-xs font-semibold text-indigo-300">{recommendationActionLabel(trade.recommended_action)}</span>
+                    <span className="text-xs font-semibold text-blue-300">{recommendationActionLabel(trade.recommended_action)}</span>
                     {recommendationActionDirection(trade.recommended_action) !== 'neutral' && recommendationActionDirection(trade.recommended_action) !== trade.direction && (
                       <div className="text-[10px] text-amber-400">Alternative setup (not preferred)</div>
                     )}