Add multi-factor conviction gate to activation

Make "qualified" mean an edge candidate, not just R:R + confidence.
The gate now also requires (all admin-configurable, defaults on):
- high conviction: recommended_action LONG_HIGH / SHORT_HIGH only
- clean read: risk_level Low (no contradicting signals)
- probable primary target: best target probability >= min (default 60)

- Shared predicate: app/services/qualification.py +
  frontend/src/lib/qualification.ts (mirrored)
- Activation config extended (min_target_probability,
  require_high_conviction, exclude_conflicts) with bool-aware
  get/update + validation
- /trades/performance switched to ?qualified_only=true, applying
  the full gate server-side; confidence breakdown stays unfiltered
- Dashboard "Qualified", Signals "Qualified only" toggle, and
  Track Record all use the one gate; Admin gains the new controls

Sentiment provider runtime config (prior change) included.

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

frontend/src/api/admin.ts

@@ -4,6 +4,8 @@ import type {
   AdminUser,
   PipelineReadiness,
   RecommendationConfig,
+  SentimentProviderConfig,
+  SentimentTestResult,
   SystemSetting,
   TickerUniverse,
   TickerUniverseBootstrapResult,
@@ -81,6 +83,28 @@ export function updateActivationSettings(payload: Partial<ActivationConfig>) {
     .then((r) => r.data);
 }
 
+export function getSentimentSettings() {
+  return apiClient
+    .get<SentimentProviderConfig>('admin/settings/sentiment')
+    .then((r) => r.data);
+}
+
+export function updateSentimentSettings(payload: {
+  provider?: string;
+  model?: string;
+  api_key?: string;
+}) {
+  return apiClient
+    .put<SentimentProviderConfig>('admin/settings/sentiment', payload)
+    .then((r) => r.data);
+}
+
+export function testSentimentSettings(ticker: string) {
+  return apiClient
+    .post<SentimentTestResult>('admin/settings/sentiment/test', { ticker })
+    .then((r) => r.data);
+}
+
 export function getTickerUniverseSetting() {
   return apiClient
     .get<TickerUniverseSetting>('admin/settings/ticker-universe')