feat(insta-lab): main.py — trends + preferences endpoints

- POST /api/insta/trends/collect — background trend collection via trend_collector.collect_all
- GET /api/insta/trends — list external trends with source/category/days filters
- GET /api/insta/preferences — return category weights (defaults seeded on init_db)
- PUT /api/insta/preferences — upsert category weights
- Modified GET /api/insta/keywords to accept source= filter (source present → list_trends, else existing list_trending_keywords, backward compatible)

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

insta-lab/tests/test_main_trends.py

@@ -0,0 +1,83 @@
+import os
+import gc
+import tempfile
+
+import pytest
+from fastapi.testclient import TestClient
+
+from app import db as db_module
+
+
+@pytest.fixture
+def client(monkeypatch):
+    fd, path = tempfile.mkstemp(suffix=".db")
+    os.close(fd)
+    monkeypatch.setattr(db_module, "DB_PATH", path)
+    db_module.init_db()
+    from app import main
+    monkeypatch.setattr(main, "DB_PATH", path)
+    with TestClient(main.app) as c:
+        yield c
+    gc.collect()
+    for ext in ("", "-wal", "-shm"):
+        try:
+            os.remove(path + ext)
+        except OSError:
+            pass
+
+
+def test_get_preferences_returns_defaults(client):
+    resp = client.get("/api/insta/preferences")
+    assert resp.status_code == 200
+    cats = {p["category"]: p["weight"] for p in resp.json()["categories"]}
+    assert cats == {"economy": 1.0, "psychology": 1.0, "celebrity": 1.0}
+
+
+def test_put_preferences_upsert(client):
+    resp = client.put("/api/insta/preferences",
+                      json={"categories": {"economy": 0.7, "psychology": 0.2, "tech": 0.5}})
+    assert resp.status_code == 200
+    cats = {p["category"]: p["weight"] for p in resp.json()["categories"]}
+    assert cats["economy"] == 0.7
+    assert cats["tech"] == 0.5
+
+
+def test_list_trends_filter(client):
+    db_module.add_external_trend({"keyword": "A", "category": "economy",
+                                  "source": "naver_popular", "score": 1.0})
+    db_module.add_external_trend({"keyword": "B", "category": "celebrity",
+                                  "source": "google_trends", "score": 0.8})
+    resp = client.get("/api/insta/trends?source=naver_popular")
+    items = resp.json()["items"]
+    assert {it["keyword"] for it in items} == {"A"}
+
+
+def test_collect_trends_kicks_background(client, monkeypatch):
+    from app import main, trend_collector
+
+    captured = {"called": False}
+
+    def fake_collect_all(cats):
+        captured["called"] = True
+        return {"naver_popular": 3, "google_trends": 2}
+
+    monkeypatch.setattr(trend_collector, "collect_all", fake_collect_all)
+    resp = client.post("/api/insta/trends/collect", json={})
+    assert resp.status_code == 200
+    task_id = resp.json()["task_id"]
+    for _ in range(20):
+        st = client.get(f"/api/insta/tasks/{task_id}").json()
+        if st["status"] in ("succeeded", "failed"):
+            break
+    assert st["status"] == "succeeded"
+    assert captured["called"] is True
+
+
+def test_list_keywords_filters_by_source(client):
+    db_module.add_trending_keyword({"keyword": "M", "category": "economy",
+                                    "score": 0.4, "articles_count": 1, "source": "manual"})
+    db_module.add_external_trend({"keyword": "N", "category": "economy",
+                                  "source": "naver_popular", "score": 0.9})
+    resp = client.get("/api/insta/keywords?source=manual")
+    items = resp.json()["items"]
+    assert {it["keyword"] for it in items} == {"M"}