feat: [additional] RAG 검색에 토큰 비용 안내 및 사용량 표시 추가

- 검색 전 비용 안내 문구 (건당 약 3~10원, AI 토큰 사용량 기록 안내)
- 검색 결과에 토큰 사용량 바 표시 (입력/출력/합계/비용)
- AiTokenHelper + AiPricingConfig 연동으로 정확한 비용 계산

app/Services/RagSearchService.php

@@ -4,6 +4,7 @@
 
 use App\Helpers\AiTokenHelper;
 use App\Models\System\AiConfig;
+use App\Models\System\AiPricingConfig;
 use Illuminate\Support\Facades\Http;
 use Illuminate\Support\Facades\Log;
 
@@ -282,7 +283,21 @@ private function callGemini(AiConfig $config, string $query, string $context, ar
             $result = $response->json();
             $answer = $result['candidates'][0]['content']['parts'][0]['text'] ?? '';
 
-            // 토큰 사용량 저장
+            // 토큰 사용량 계산
+            $usage = $result['usageMetadata'] ?? [];
+            $promptTokens = $usage['promptTokenCount'] ?? 0;
+            $completionTokens = $usage['candidatesTokenCount'] ?? 0;
+            $totalTokens = $usage['totalTokenCount'] ?? 0;
+
+            // 비용 계산
+            $pricing = AiPricingConfig::getActivePricing('gemini');
+            $inputPrice = $pricing ? (float) $pricing->input_price_per_million / 1_000_000 : 0.10 / 1_000_000;
+            $outputPrice = $pricing ? (float) $pricing->output_price_per_million / 1_000_000 : 0.40 / 1_000_000;
+            $costUsd = ($promptTokens * $inputPrice) + ($completionTokens * $outputPrice);
+            $exchangeRate = AiPricingConfig::getExchangeRate();
+            $costKrw = $costUsd * $exchangeRate;
+
+            // 토큰 사용량 DB 저장
             AiTokenHelper::saveGeminiUsage($result, $result['modelVersion'] ?? $config->model, 'RAG검색');
 
             // 참조 문서 목록 추출
@@ -297,6 +312,13 @@ private function callGemini(AiConfig $config, string $query, string $context, ar
                 'references' => $references,
                 'searched_count' => count($documents),
                 'model' => $config->model,
+                'token_usage' => [
+                    'prompt_tokens' => $promptTokens,
+                    'completion_tokens' => $completionTokens,
+                    'total_tokens' => $totalTokens,
+                    'cost_usd' => round($costUsd, 6),
+                    'cost_krw' => round($costKrw, 2),
+                ],
             ];
 
         } catch (\Exception $e) {

resources/views/additional/rag/index.blade.php

@@ -65,6 +65,17 @@
     .rag-answer-body blockquote { border-left: 3px solid #3b82f6; padding-left: 14px; margin: 12px 0; color: #64748b; }
     .rag-answer-body strong { font-weight: 600; color: #1e293b; }
 
+    /* 토큰 비용 바 */
+    .rag-token-bar { display: flex; align-items: center; gap: 14px; background: #fffbeb; border: 1px solid #fde68a; border-radius: 8px; padding: 10px 16px; margin-bottom: 16px; flex-wrap: wrap; }
+    .rag-token-item { display: flex; align-items: center; gap: 5px; font-size: 0.75rem; color: #92400e; }
+    .rag-token-item .label { color: #a16207; }
+    .rag-token-item .value { font-weight: 600; }
+    .rag-token-sep { width: 1px; height: 14px; background: #fde68a; }
+
+    /* 비용 안내 */
+    .rag-cost-notice { background: #f0f9ff; border: 1px solid #bae6fd; border-radius: 8px; padding: 10px 16px; margin-bottom: 24px; display: flex; align-items: flex-start; gap: 8px; font-size: 0.78rem; color: #0369a1; line-height: 1.5; }
+    .rag-cost-notice svg { width: 16px; height: 16px; flex-shrink: 0; margin-top: 1px; }
+
     /* 참조 문서 */
     .rag-refs { background: #f8fafc; border: 1px solid #e2e8f0; border-radius: 10px; padding: 16px 20px; }
     .rag-refs-title { font-size: 0.78rem; font-weight: 600; color: #64748b; margin-bottom: 10px; display: flex; align-items: center; gap: 6px; }
@@ -127,6 +138,12 @@
         </div>
     </div>
 
+    {{-- 비용 안내 --}}
+    <div class="rag-cost-notice">
+        <svg fill="none" stroke="currentColor" viewBox="0 0 24 24"><path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M13 16h-1v-4h-1m1-4h.01M21 12a9 9 0 11-18 0 9 9 0 0118 0z" /></svg>
+        <span>검색 1회당 Gemini API 토큰이 소모됩니다. 관련 문서(최대 100KB)를 컨텍스트로 전달하므로 약 <strong>25,000~50,000 토큰</strong>이 사용되며, 예상 비용은 <strong>건당 약 3~10원</strong>입니다. 사용 내역은 시스템설정 > AI 토큰 사용량에 기록됩니다.</span>
+    </div>
+
     {{-- 검색 --}}
     <div class="rag-search">
         <input type="text" class="rag-search-input" id="ragQuery" placeholder="SAM 프로젝트에 대해 질문하세요... (예: API 개발 규칙, 데이터베이스 구조)" autocomplete="off">
@@ -227,7 +244,37 @@ function setQuery(text) {
 }
 
 function renderAnswer(data) {
-    let html = `
+    let html = '';
+
+    // 토큰 사용량 바
+    if (data.token_usage) {
+        const t = data.token_usage;
+        html += `
+            <div class="rag-token-bar">
+                <div class="rag-token-item">
+                    <span class="label">입력</span>
+                    <span class="value">${Number(t.prompt_tokens).toLocaleString()}</span>
+                </div>
+                <div class="rag-token-sep"></div>
+                <div class="rag-token-item">
+                    <span class="label">출력</span>
+                    <span class="value">${Number(t.completion_tokens).toLocaleString()}</span>
+                </div>
+                <div class="rag-token-sep"></div>
+                <div class="rag-token-item">
+                    <span class="label">합계</span>
+                    <span class="value">${Number(t.total_tokens).toLocaleString()} tokens</span>
+                </div>
+                <div class="rag-token-sep"></div>
+                <div class="rag-token-item">
+                    <span class="label">비용</span>
+                    <span class="value">$${t.cost_usd.toFixed(4)} (${Math.round(t.cost_krw).toLocaleString()}원)</span>
+                </div>
+            </div>
+        `;
+    }
+
+    html += `
         <div class="rag-answer">
             <div class="rag-answer-header">
                 <svg fill="none" stroke="currentColor" viewBox="0 0 24 24"><path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M9.663 17h4.673M12 3v1m6.364 1.636l-.707.707M21 12h-1M4 12H3m3.343-5.657l-.707-.707m2.828 9.9a5 5 0 117.072 0l-.548.547A3.374 3.374 0 0014 18.469V19a2 2 0 11-4 0v-.531c0-.895-.356-1.754-.988-2.386l-.548-.547z" /></svg>