feat: portfolio context injection + AI call log viewer

Portfolio context (portfolio_context.py):
- get_open_trades_with_moves(): fetches open trades + 1d/5d yfinance price moves
- get_portfolio_concentration(): counts by asset_class
- build_portfolio_context_block(): formatted prompt block with strict AI instructions
  (no double positions, flag contradictions, avoid overweight classes)

AI call logging:
- ai_call_logs table in DB (run_id, call_type, system/user prompt, response, tokens, ms)
- _chat() now accepts log_meta dict → saves call to DB non-blocking after each call
- suggest and score_batch calls pass run_id + call_type for full traceability

auto_cycle.py:
- Builds portfolio context before snapshot and both AI calls
- Context snapshot now includes portfolio_open_positions key

SystemLogs.tsx:
- "Contexte IA" tab gains sub-tabs: Contexte / Appels IA
- AiCallRow: expandable with 3 panes (user prompt / system prompt / response)
  shows model, tokens breakdown, duration, call type badge

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

frontend/src/hooks/useApi.ts

@@ -888,6 +888,14 @@ export const useReplayCycle = () =>
       api.post(`/cycle/contexts/${runId}/replay`, { override_notes: notes ?? null }).then(r => r.data),
   })
 
+export const useAiCallLogs = (runId: string | null) =>
+  useQuery({
+    queryKey: ['ai-call-logs', runId],
+    queryFn: () => api.get(`/cycle/ai-calls/${runId}`).then(r => r.data),
+    enabled: !!runId,
+    staleTime: 60_000,
+  })
+
 // ── IV Watchlist Management ───────────────────────────────────────────────────
 
 export const useWatchlistTickers = () =>