fix: split Perplexity into 3 focused queries matching research methodology

Single mega-query returns empty results. Split into:
B4a. Instagram + YouTube (most important, focused search)
B4b. Facebook + TikTok + Naver Blog + Kakao
B4c. 강남언니 + review platforms

Each query is short and focused — matches the proven pattern of
2-5 keyword searches that Perplexity handles well.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

supabase/functions/discover-channels/index.ts

@@ -284,83 +284,89 @@ Deno.serve(async (req) => {
       } catch { /* skip */ }
     })());
 
-    // ─── B4. Perplexity sonar-pro: Online Presence 종합 리서치 에이전트 ───
+    // ─── B4. Perplexity: 3 separate focused queries (like the research methodology) ───
     let perplexityResearch: Record<string, unknown> | null = null;
 
     if (PERPLEXITY_API_KEY) {
+      const ppxHeaders = { "Content-Type": "application/json", Authorization: `Bearer ${PERPLEXITY_API_KEY}` };
+      const ppxSystem = "You are a social media researcher. Search the web and find accounts. Respond ONLY with valid JSON, no explanation.";
+
+      // B4a. Instagram + YouTube 검색 (가장 중요)
       stageBTasks.push((async () => {
         try {
           const res = await fetch("https://api.perplexity.ai/chat/completions", {
-            method: "POST",
-            headers: { "Content-Type": "application/json", Authorization: `Bearer ${PERPLEXITY_API_KEY}` },
+            method: "POST", headers: ppxHeaders,
             body: JSON.stringify({
               model: "sonar",
               messages: [
-                { role: "system", content: RESEARCH_SYSTEM_PROMPT },
-                { role: "user", content: buildResearchUserPrompt(resolvedName, url) },
+                { role: "system", content: ppxSystem },
+                { role: "user", content: `${resolvedName} 성형외과 공식 인스타그램 계정과 유튜브 채널을 찾아줘. 인스타는 여러 계정(국문, 영문, 원장 등)이 있을 수 있어.\n\n{"instagram": ["@handle1", "@handle2"], "youtube": ["@handle_or_url"]}` },
               ],
               temperature: 0.1,
             }),
           });
           const data = await res.json();
           let text = data.choices?.[0]?.message?.content || "";
-          // Strip markdown code blocks
-          const jsonMatch = text.match(/```(?:json)?\n?([\s\S]*?)```/);
-          if (jsonMatch) text = jsonMatch[1];
-          // Try to find JSON in mixed text
-          const jsonStart = text.indexOf('{');
-          const jsonEnd = text.lastIndexOf('}');
-          if (jsonStart >= 0 && jsonEnd > jsonStart) {
-            text = text.slice(jsonStart, jsonEnd + 1);
+          const m = text.match(/\{[\s\S]*\}/);
+          if (m) {
+            const parsed = JSON.parse(m[0]);
+            const ig = Array.isArray(parsed.instagram) ? parsed.instagram : parsed.instagram ? [parsed.instagram] : [];
+            const yt = Array.isArray(parsed.youtube) ? parsed.youtube : parsed.youtube ? [parsed.youtube] : [];
+            ig.forEach((h: unknown) => { if (h && typeof h === 'string') apiHandles.instagram!.push(h); });
+            yt.forEach((h: unknown) => { if (h && typeof h === 'string') apiHandles.youtube!.push(h); });
           }
-          const parsed = JSON.parse(text);
+        } catch { /* skip */ }
+      })());
+
+      // B4b. Facebook + TikTok + 네이버 블로그 + 카카오
+      stageBTasks.push((async () => {
+        try {
+          const res = await fetch("https://api.perplexity.ai/chat/completions", {
+            method: "POST", headers: ppxHeaders,
+            body: JSON.stringify({
+              model: "sonar",
+              messages: [
+                { role: "system", content: ppxSystem },
+                { role: "user", content: `${resolvedName} 병원의 페이스북, 틱톡, 네이버블로그, 카카오채널 계정을 검색해줘.\n\n{"facebook": "page_or_url", "tiktok": "@handle", "naverBlog": "blogId", "kakao": "channelId"}` },
+              ],
+              temperature: 0.1,
+            }),
+          });
+          const data = await res.json();
+          let text = data.choices?.[0]?.message?.content || "";
+          const m = text.match(/\{[\s\S]*\}/);
+          if (m) {
+            const parsed = JSON.parse(m[0]);
+            if (parsed.facebook && typeof parsed.facebook === 'string') apiHandles.facebook!.push(parsed.facebook);
+            if (parsed.tiktok && typeof parsed.tiktok === 'string') apiHandles.tiktok!.push(parsed.tiktok);
+            if (parsed.naverBlog && typeof parsed.naverBlog === 'string') apiHandles.naverBlog!.push(parsed.naverBlog);
+            if (parsed.kakao && typeof parsed.kakao === 'string') apiHandles.kakao!.push(parsed.kakao);
+          }
+        } catch { /* skip */ }
+      })());
+
+      // B4c. 강남언니 + 리뷰 플랫폼
+      stageBTasks.push((async () => {
+        try {
+          const res = await fetch("https://api.perplexity.ai/chat/completions", {
+            method: "POST", headers: ppxHeaders,
+            body: JSON.stringify({
+              model: "sonar",
+              messages: [
+                { role: "system", content: ppxSystem },
+                { role: "user", content: `${resolvedName} 병원이 강남언니(gangnamunni.com)에 등록되어있는지 검색해줘. URL도 찾아줘.\n\n{"gangnamUnni": {"registered": true, "url": "https://gangnamunni.com/hospitals/...", "rating": 9.5, "reviews": 1000}}` },
+              ],
+              temperature: 0.1,
+            }),
+          });
+          const data = await res.json();
+          let text = data.choices?.[0]?.message?.content || "";
+          const m = text.match(/\{[\s\S]*\}/);
+          if (m) {
+            const parsed = JSON.parse(m[0]);
             perplexityResearch = parsed;
-
-          // Extract handles from structured channels data
-          const ch = parsed.channels || {};
-
-          // Instagram
-          const igAccounts = Array.isArray(ch.instagram) ? ch.instagram : [];
-          for (const ig of igAccounts) {
-            const handle = typeof ig === 'string' ? ig : (ig?.handle || ig?.url || '');
-            if (handle) apiHandles.instagram!.push(String(handle));
+            if (parsed.gangnamUnni?.url) gangnamUnniHintUrl = String(parsed.gangnamUnni.url);
           }
-
-          // YouTube
-          const ytChannels = Array.isArray(ch.youtube) ? ch.youtube : ch.youtube ? [ch.youtube] : [];
-          for (const yt of ytChannels) {
-            const handle = typeof yt === 'string' ? yt : (yt?.handle || yt?.channelUrl || '');
-            if (handle) apiHandles.youtube!.push(String(handle));
-          }
-
-          // Facebook
-          if (ch.facebook) {
-            const fb = typeof ch.facebook === 'string' ? ch.facebook : (ch.facebook?.handle || ch.facebook?.url || '');
-            if (fb) apiHandles.facebook!.push(String(fb));
-          }
-
-          // TikTok
-          if (ch.tiktok) {
-            const tk = typeof ch.tiktok === 'string' ? ch.tiktok : (ch.tiktok?.handle || ch.tiktok?.url || '');
-            if (tk) apiHandles.tiktok!.push(String(tk));
-          }
-
-          // Naver Blog
-          if (ch.naverBlog) {
-            const nb = typeof ch.naverBlog === 'string' ? ch.naverBlog : (ch.naverBlog?.blogId || ch.naverBlog?.url || '');
-            if (nb) apiHandles.naverBlog!.push(String(nb));
-          }
-
-          // Kakao
-          if (ch.kakao) {
-            const kk = typeof ch.kakao === 'string' ? ch.kakao : (ch.kakao?.channelId || ch.kakao?.url || '');
-            if (kk) apiHandles.kakao!.push(String(kk));
-          }
-
-          // Platform presence hints
-          const platforms = parsed.platforms || {};
-          if (platforms.gangnamUnni?.url) gangnamUnniHintUrl = String(platforms.gangnamUnni.url);
-
         } catch { /* skip */ }
       })());
     }