refactor: v2.0 完全解耦 — 阿里云内闭环

- 删除 VOC_DATA_DIR / get_voc_conn（不再跨云直读 SQLite）
- 案例 DB 自带 comments 表，自包含所有数据
- 新增 POST /import-voc：通过 VOC 公网 API 导入评论
- VOC_API_BASE 环境变量控制 API 地址
- 新增 httpx 依赖

backend/db.py

@@ -1,9 +1,11 @@
 """
-黑手党提案 — 数据库管理
+黑手党提案 — 数据库管理（完全独立，阿里云内闭环）
 
-双库设计：
-  1. 案例 DB（读写）：每个提案案例一个 SQLite，存分析结果
-  2. VOC DB（只读）：读取共享 VOC 数据层的原始评论
+每个提案案例一个 SQLite 文件，自包含所有数据：
+  - case_card：案例元信息
+  - comments：从 VOC API 导入的评论（本地副本）
+  - ude_sentences / ude_clusters：UDE 分析结果
+  - conflicts / proposal_sections：后续阶段
 """
 import os
 import sqlite3
@@ -17,10 +19,11 @@ load_dotenv()
 DATA_DIR = Path(__file__).parent / "data"
 DATA_DIR.mkdir(exist_ok=True)
 
-VOC_DATA_DIR = Path(os.getenv("VOC_DATA_DIR", ""))
+# VOC 公网 API（腾讯云，跨云只读访问）
+VOC_API_BASE = os.getenv("VOC_API_BASE", "https://brand.brainwork.club/voc/api/research")
 
 
-# ═══════════ 案例 DB（读写） ═══════════
+# ═══════════ Schema ═══════════
 
 CASE_SCHEMA = """
 CREATE TABLE IF NOT EXISTS case_card (
@@ -29,13 +32,25 @@ CREATE TABLE IF NOT EXISTS case_card (
     focus_product TEXT,
     competitors TEXT,
     voc_research_id TEXT,
+    voc_api_base TEXT,
     created_at TEXT DEFAULT (datetime('now')),
     status TEXT DEFAULT 'draft'
 );
 
+CREATE TABLE IF NOT EXISTS comments (
+    id INTEGER PRIMARY KEY AUTOINCREMENT,
+    voc_id INTEGER,
+    platform TEXT,
+    text TEXT NOT NULL,
+    like_count INTEGER DEFAULT 0,
+    published_at TEXT,
+    imported_at TEXT DEFAULT (datetime('now')),
+    UNIQUE(voc_id)
+);
+
 CREATE TABLE IF NOT EXISTS ude_sentences (
     id INTEGER PRIMARY KEY AUTOINCREMENT,
-    voc_comment_id INTEGER,
+    comment_id INTEGER REFERENCES comments(id),
     ude_text TEXT NOT NULL,
     confidence REAL DEFAULT 0.5,
     vector TEXT,
@@ -73,8 +88,10 @@ CREATE TABLE IF NOT EXISTS proposal_sections (
 """
 
 
+# ═══════════ 案例 DB ═══════════
+
 def get_case_conn(case_id: str) -> sqlite3.Connection:
-    """获取案例 DB 连接（读写）"""
+    """获取案例 DB 连接"""
     path = DATA_DIR / f"{case_id}.db"
     if not path.exists():
         raise FileNotFoundError(f"案例 {case_id} 不存在")
@@ -93,8 +110,8 @@ def init_case_db(brand_name: str, category: str = "", focus_product: str = "",
     conn.row_factory = sqlite3.Row
     conn.executescript(CASE_SCHEMA)
     conn.execute(
-        "INSERT INTO case_card (brand_name, category, focus_product, competitors, voc_research_id) VALUES (?,?,?,?,?)",
-        (brand_name, category, focus_product, competitors, voc_research_id)
+        "INSERT INTO case_card (brand_name, category, focus_product, competitors, voc_research_id, voc_api_base) VALUES (?,?,?,?,?,?)",
+        (brand_name, category, focus_product, competitors, voc_research_id, VOC_API_BASE)
     )
     conn.commit()
     conn.close()
@@ -111,11 +128,13 @@ def list_cases() -> list[dict]:
             conn.row_factory = sqlite3.Row
             card = conn.execute("SELECT * FROM case_card LIMIT 1").fetchone()
             if card:
+                comment_count = conn.execute("SELECT count(*) FROM comments").fetchone()[0]
                 ude_count = conn.execute("SELECT count(*) FROM ude_sentences").fetchone()[0]
                 cluster_count = conn.execute("SELECT count(*) FROM ude_clusters").fetchone()[0]
                 cases.append({
                     "case_id": case_id,
                     **dict(card),
+                    "comment_count": comment_count,
                     "ude_count": ude_count,
                     "cluster_count": cluster_count,
                 })
@@ -123,45 +142,3 @@ def list_cases() -> list[dict]:
         except Exception:
             pass
     return cases
-
-
-# ═══════════ VOC DB（只读） ═══════════
-
-def get_voc_conn(voc_research_id: str) -> sqlite3.Connection:
-    """只读访问共享 VOC 数据"""
-    if not VOC_DATA_DIR.exists():
-        raise FileNotFoundError(f"VOC 数据目录不存在: {VOC_DATA_DIR}")
-    path = VOC_DATA_DIR / f"{voc_research_id}.db"
-    if not path.exists():
-        raise FileNotFoundError(f"VOC 研究 {voc_research_id} 不存在")
-    conn = sqlite3.connect(f"file:{path}?mode=ro", uri=True)
-    conn.row_factory = sqlite3.Row
-    return conn
-
-
-def list_voc_researches() -> list[dict]:
-    """列出共享 VOC 数据层中的所有研究"""
-    if not VOC_DATA_DIR.exists():
-        return []
-    researches = []
-    for db_file in sorted(VOC_DATA_DIR.glob("*.db")):
-        if db_file.name in ("global_cache.db", "agent_sessions.db"):
-            continue
-        rid = db_file.stem
-        try:
-            conn = sqlite3.connect(f"file:{db_file}?mode=ro", uri=True)
-            conn.row_factory = sqlite3.Row
-            card = conn.execute("SELECT brand_name FROM research_card LIMIT 1").fetchone()
-            comment_count = conn.execute(
-                "SELECT count(*) FROM comments WHERE length(text) > 10"
-            ).fetchone()[0]
-            conn.close()
-            if card and comment_count > 0:
-                researches.append({
-                    "research_id": rid,
-                    "brand_name": card["brand_name"],
-                    "comment_count": comment_count,
-                })
-        except Exception:
-            pass
-    return researches