feat: 独立后端（共享 VOC 数据层 + 自有分析存储）

- backend/server.py: FastAPI 端口 8093
- backend/db.py: 双库设计（案例 DB 读写 + VOC DB 只读）
- backend/tools/ude_extract.py: UDE 转写 + 向量聚类
- backend/prompts/voc_to_ude.txt: TOC 7条规范约束
- 已部署至 /opt/apps/mafia-proposal/ (systemd)
- Nginx /copaw/mafia/api/ 代理已配置

backend/db.py

@@ -0,0 +1,167 @@
+"""
+黑手党提案 — 数据库管理
+
+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
+"""
+import os
+import sqlite3
+import uuid
+from pathlib import Path
+
+from dotenv import load_dotenv
+
+load_dotenv()
+
+DATA_DIR = Path(__file__).parent / "data"
+DATA_DIR.mkdir(exist_ok=True)
+
+VOC_DATA_DIR = Path(os.getenv("VOC_DATA_DIR", ""))
+
+
+# ═══════════ 案例 DB（读写） ═══════════
+
+CASE_SCHEMA = """
+CREATE TABLE IF NOT EXISTS case_card (
+    brand_name TEXT NOT NULL,
+    category TEXT,
+    focus_product TEXT,
+    competitors TEXT,
+    voc_research_id TEXT,
+    created_at TEXT DEFAULT (datetime('now')),
+    status TEXT DEFAULT 'draft'
+);
+
+CREATE TABLE IF NOT EXISTS ude_sentences (
+    id INTEGER PRIMARY KEY AUTOINCREMENT,
+    voc_comment_id INTEGER,
+    ude_text TEXT NOT NULL,
+    confidence REAL DEFAULT 0.5,
+    vector TEXT,
+    cluster_id INTEGER DEFAULT -1,
+    created_at TEXT DEFAULT (datetime('now'))
+);
+
+CREATE TABLE IF NOT EXISTS ude_clusters (
+    id INTEGER PRIMARY KEY AUTOINCREMENT,
+    representative_ude TEXT,
+    coverage INTEGER,
+    sample_voices TEXT,
+    user_label TEXT,
+    confirmed INTEGER DEFAULT 0
+);
+
+CREATE TABLE IF NOT EXISTS conflicts (
+    id INTEGER PRIMARY KEY AUTOINCREMENT,
+    ude_cluster_id INTEGER,
+    goal TEXT,
+    need TEXT,
+    prerequisite TEXT,
+    convention TEXT,
+    conflict_type TEXT,
+    description TEXT
+);
+
+CREATE TABLE IF NOT EXISTS proposal_sections (
+    id INTEGER PRIMARY KEY AUTOINCREMENT,
+    section TEXT,
+    content TEXT,
+    version INTEGER DEFAULT 1,
+    updated_at TEXT DEFAULT (datetime('now'))
+);
+"""
+
+
+def get_case_conn(case_id: str) -> sqlite3.Connection:
+    """获取案例 DB 连接（读写）"""
+    path = DATA_DIR / f"{case_id}.db"
+    if not path.exists():
+        raise FileNotFoundError(f"案例 {case_id} 不存在")
+    conn = sqlite3.connect(str(path))
+    conn.row_factory = sqlite3.Row
+    conn.execute("PRAGMA journal_mode=WAL")
+    return conn
+
+
+def init_case_db(brand_name: str, category: str = "", focus_product: str = "",
+                 competitors: str = "[]", voc_research_id: str = None) -> str:
+    """创建新案例，返回 case_id"""
+    case_id = uuid.uuid4().hex[:8]
+    path = DATA_DIR / f"{case_id}.db"
+    conn = sqlite3.connect(str(path))
+    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)
+    )
+    conn.commit()
+    conn.close()
+    return case_id
+
+
+def list_cases() -> list[dict]:
+    """列出所有案例"""
+    cases = []
+    for db_file in sorted(DATA_DIR.glob("*.db")):
+        case_id = db_file.stem
+        try:
+            conn = sqlite3.connect(str(db_file))
+            conn.row_factory = sqlite3.Row
+            card = conn.execute("SELECT * FROM case_card LIMIT 1").fetchone()
+            if card:
+                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),
+                    "ude_count": ude_count,
+                    "cluster_count": cluster_count,
+                })
+            conn.close()
+        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