feat: risk tier selector on Trading page + confidence filter on Recommendations

- Trading page: added conservative/moderate/aggressive selector that
  updates the trading engine config via PUT /api/trading/config
- Recommendations page: added risk tier dropdown that defaults to the
  engine's current tier and filters recs by the tier's min_confidence
- Backend: added min_confidence query param to GET /api/recommendations
- Risk tier thresholds: conservative ≥0.75, moderate ≥0.55, aggressive ≥0.40

frontend/src/pages/Recommendations.tsx

@@ -1,14 +1,33 @@
 import { useState } from 'react';
 import { useNavigate } from '@tanstack/react-router';
 import { useRecommendations } from '../api/hooks';
+import { useTradingStatus } from '../api/tradingHooks';
 import { DataTable, type Column } from '../components/DataTable';
 import { StatusBadge, ConfidenceBar, LoadingSpinner, TickerFilter } from '../components/ui';
 import type { Recommendation } from '../api/hooks';
 
+const RISK_TIER_CONFIDENCE: Record<string, number> = {
+  conservative: 0.75,
+  moderate: 0.55,
+  aggressive: 0.40,
+};
+
 export function RecommendationsPage() {
   const navigate = useNavigate();
   const [ticker, setTicker] = useState('');
-  const { data, isLoading } = useRecommendations({ ticker: ticker || undefined, limit: 100 });
+  const { data: tradingStatus } = useTradingStatus();
+  const engineTier = tradingStatus?.risk_tier ?? 'moderate';
+  const [riskTier, setRiskTier] = useState<string | null>(null);
+
+  // Use engine tier as default, allow override
+  const activeTier = riskTier ?? engineTier;
+  const minConfidence = RISK_TIER_CONFIDENCE[activeTier] ?? 0.55;
+
+  const { data, isLoading } = useRecommendations({
+    ticker: ticker || undefined,
+    min_confidence: minConfidence,
+    limit: 100,
+  });
 
   const columns: Column<Recommendation>[] = [
     { key: 'ticker', header: 'Ticker', className: 'font-mono font-semibold text-brand-300' },
@@ -25,7 +44,24 @@ export function RecommendationsPage() {
     <div>
       <div className="mb-4 flex items-center justify-between">
         <h1 className="text-xl font-semibold text-gray-100">Recommendations</h1>
-        <TickerFilter value={ticker} onChange={setTicker} />
+        <div className="flex items-center gap-3">
+          <div className="flex items-center gap-2">
+            <label htmlFor="risk-tier-filter" className="text-xs text-gray-500">Risk Tier</label>
+            <select
+              id="risk-tier-filter"
+              value={activeTier}
+              onChange={(e) => setRiskTier(e.target.value)}
+              className="rounded-md border border-surface-700 bg-surface-900 px-2 py-1.5 text-sm text-gray-200 focus:border-brand-500 focus:outline-none"
+            >
+              {Object.entries(RISK_TIER_CONFIDENCE).map(([tier, conf]) => (
+                <option key={tier} value={tier}>
+                  {tier.charAt(0).toUpperCase() + tier.slice(1)} (≥{conf})
+                </option>
+              ))}
+            </select>
+          </div>
+          <TickerFilter value={ticker} onChange={setTicker} />
+        </div>
       </div>
       <DataTable<Recommendation>
         data={data ?? []}

frontend/src/pages/Trading.tsx

@@ -10,7 +10,7 @@ import {
   useCompetitiveStatus,
   useToggleCompetitive,
 } from '../api/hooks';
-import { useResetPaperTrading } from '../api/tradingHooks';
+import { useResetPaperTrading, useTradingStatus, useUpdateTradingConfig } from '../api/tradingHooks';
 import { StatusBadge, LoadingSpinner, Card } from '../components/ui';
 
 export function TradingPage() {
@@ -21,6 +21,8 @@ export function TradingPage() {
   const { data: competitiveStatus } = useCompetitiveStatus();
   const setMode = useSetTradingMode();
   const resetTrading = useResetPaperTrading();
+  const { data: tradingStatus } = useTradingStatus();
+  const updateConfig = useUpdateTradingConfig();
   const reviewApproval = useReviewApproval();
   const toggleMacro = useToggleMacro();
   const toggleCompetitive = useToggleCompetitive();
@@ -95,6 +97,41 @@ export function TradingPage() {
         isResetting={resetTrading.isPending}
       />
 
+      {/* Risk Tier */}
+      <Card>
+        <h2 className="mb-3 text-sm font-medium text-gray-400">Risk Tier</h2>
+        <p className="mb-3 text-[10px] text-gray-600">
+          Controls confidence gates, position sizing, and portfolio heat limits for the trading engine.
+        </p>
+        <div className="flex items-center gap-3">
+          {(['conservative', 'moderate', 'aggressive'] as const).map((tier) => {
+            const currentTier = tradingStatus?.risk_tier ?? 'moderate';
+            const descriptions: Record<string, string> = {
+              conservative: 'Min confidence 0.75, max 5% position, 10% heat',
+              moderate: 'Min confidence 0.55, max 10% position, 20% heat',
+              aggressive: 'Min confidence 0.40, max 15% position, 30% heat',
+            };
+            return (
+              <button
+                key={tier}
+                onClick={() => {
+                  if (tier !== currentTier) updateConfig.mutate({ risk_tier: tier });
+                }}
+                className={`rounded-md px-4 py-2 text-sm font-medium capitalize transition-colors ${
+                  currentTier === tier
+                    ? 'bg-brand-600 text-white'
+                    : 'border border-surface-700 bg-surface-900 text-gray-400 hover:bg-surface-800'
+                }`}
+                aria-pressed={currentTier === tier}
+                title={descriptions[tier]}
+              >
+                {tier}
+              </button>
+            );
+          })}
+        </div>
+      </Card>
+
       {/* Macro Signal Layer Toggle */}
       <Card>
         <h2 className="mb-3 text-sm font-medium text-gray-400">Macro Signal Layer</h2>