重构：flask_app.py 拆分为 db/helpers/routes/seed_data + Blueprint

- flask_app.py 1166行→33行纯入口
- 新建 db.py（配置+连接+SQL工具）
- 新建 helpers.py（attach_common/monthly_finance/add_file_index）
- 新建 routes.py（全路由 Blueprint + 装饰器 + TABLES）
- 新建 migrations/seed_data.py（seed_db 搬迁）
- migrations/{tables,columns,data_fixes,seed}.py 改 import 为 from db
- 删除死代码 init_db（228行）+ latest_followup（10行）
- 反向依赖消除：migrations 不再 import flask_app
- 前端零改动，URL 不变

backend/helpers.py

@@ -0,0 +1,105 @@
+# helpers.py — 业务查询辅助函数
+# 依赖：db.py；被 routes.py 和 migrations/seed_data.py 调用
+
+import json
+from pathlib import Path
+from db import _exec, rows, one
+
+
+def add_file_index(conn, module, owner_id, owner_version, category, path, external=True):
+    path = Path(path)
+    if not path.exists():
+        return
+    _exec(conn,
+        """INSERT INTO file_assets
+        (module,owner_id,owner_version,file_category,file_name,file_type,file_size,file_path,is_external)
+        VALUES (?,?,?,?,?,?,?,?,?)""",
+        (module, owner_id, owner_version, category, path.name, path.suffix.lower().lstrip("."), path.stat().st_size, str(path), 1 if external else 0),
+    )
+
+
+def attach_common(conn, resource, items):
+    """批量加载 followups 和 files，避免 N+1 查询"""
+    if not items:
+        return items
+    target_map = {"sales": "sales", "proposals": "proposal", "operations": "operation", "products": "product"}
+    target_type = target_map.get(resource)
+    ids = [item["id"] for item in items]
+
+    # 批量查 followups（一次性 IN 查询）
+    if target_type:
+        placeholders = ",".join(["?"] * len(ids))
+        all_followups = rows(
+            conn,
+            f"SELECT * FROM follow_up_records WHERE target_type=? AND target_id IN ({placeholders}) ORDER BY followed_at DESC, id DESC",
+            [target_type] + ids,
+        )
+        followups_by_id = {}
+        for fu in all_followups:
+            followups_by_id.setdefault(fu["target_id"], []).append(fu)
+        for item in items:
+            item["followups"] = followups_by_id.get(item["id"], [])
+            item["latest_follow_up_record"] = item["followups"][0]["content"] if item["followups"] else ""
+
+    # 批量查 files（proposals + operations）
+    file_modules = {"proposals": "proposal", "operations": "operation"}
+    if resource in file_modules:
+        module = file_modules[resource]
+        placeholders = ",".join(["?"] * len(ids))
+        all_files = rows(
+            conn,
+            f"SELECT * FROM file_assets WHERE module=? AND owner_id IN ({placeholders}) ORDER BY id DESC",
+            [module] + ids,
+        )
+        files_by_id = {}
+        for f in all_files:
+            files_by_id.setdefault(f["owner_id"], []).append(f)
+        for item in items:
+            item["files"] = files_by_id.get(item["id"], [])
+
+    return items
+
+
+def monthly_finance(conn, tenant="科普·无界"):
+    months = [f"2026-{m:02d}" for m in range(1, 13)]
+    pfs = rows(conn,
+        "SELECT sign_amount, sign_month, status, budget_data FROM project_finances WHERE tenant=? AND status='已签约'",
+        [tenant])
+
+    parsed_budgets = []
+    for pf in pfs:
+        try:
+            budget = json.loads(pf.get("budget_data") or "[]")
+        except (json.JSONDecodeError, TypeError):
+            budget = []
+        budget_map = {}
+        for b in budget:
+            key = (b.get("month") or "").replace("-", "_")
+            budget_map[key] = {
+                "rev": float(b.get("rev") or 0),
+                "gross": float(b.get("gross") or 0),
+                "payment": float(b.get("payment") or 0),
+                "cost": float(b.get("cost") or 0),
+            }
+        parsed_budgets.append((pf, budget_map))
+
+    data = []
+    for month in months:
+        key = month.replace("-", "_")
+        revenue = gross = payment = cost = sign = 0
+        for pf, budget_map in parsed_budgets:
+            if pf["status"] == "已签约" and (pf.get("sign_month") or "") == month:
+                sign += float(pf["sign_amount"] or 0)
+            b = budget_map.get(key)
+            if b:
+                revenue += b["rev"]
+                gross += b["gross"]
+                payment += b["payment"]
+                cost += b["cost"]
+        data.append({
+            "month": month, "revenue": revenue,
+            "labor": 0, "expense": 0, "purchase": 0,
+            "gross": gross,
+            "sign": sign, "payment": payment, "cost": cost,
+        })
+    return data