feat(llm): add LLM call recording with admin panel integration

- llm.Adapter: SetCallLogger hook for recording every API call
- llm.CallLogger: ring-buffer with Recent+Stats for admin API
- main.go: wire DeepSeek adapter to CallLogger
- Fix: single CallLogger instance for both recording and display
- Metrics: model name, duration, success/fail, tokens
- All 16 packages pass

backend/services/ai-core/background/thinker.go

@@ -4,7 +4,7 @@ package background
 
 import (
 	"context"
-	"log"
+	"git.yeij.top/AskaEth/Cyrene_v2/internal/logger"
 	"sync"
 	"time"
 )
@@ -45,19 +45,19 @@ func New(enabled bool, thinkInterval, silenceTimeout time.Duration) *Thinker {
 // Start begins the background thinking loops.
 func (t *Thinker) Start(ctx context.Context) {
 	if !t.enabled {
-		log.Println("[thinker] background thinking disabled")
+		logger.Info("[thinker] background thinking disabled")
 		return
 	}
 
 	go t.silenceLoop(ctx)
 	go t.postChatLoop(ctx)
-	log.Printf("[thinker] started (interval=%v, silence=%v)", t.thinkInterval, t.silenceTimeout)
+	logger.Infof("[thinker] started (interval=%v, silence=%v)", t.thinkInterval, t.silenceTimeout)
 }
 
 // Stop shuts down the thinker.
 func (t *Thinker) Stop() {
 	close(t.stopCh)
-	log.Println("[thinker] stopped")
+	logger.Info("[thinker] stopped")
 }
 
 // TriggerPostChat schedules a post-chat think after a conversation.
@@ -140,7 +140,7 @@ func (t *Thinker) generateThought(trigger string, sessionID string) {
 	}
 	t.mu.Unlock()
 
-	log.Printf("[thinker] %s thought generated for session %s", trigger, sessionID)
+	logger.Infof("[thinker] %s thought generated for session %s", trigger, sessionID)
 }
 
 // RecentThoughts returns the most recent thoughts.