财务项目详情升级：任务管理tab + 项目编号 + 执行信息 + 后端重构

后端重构：
- flask_app.py 拆分为 db.py/helpers.py/routes.py/seed_data.py + Blueprint
- 删除死代码 init_db/latest_followup，净减 240 行
- migrations 反向依赖消除

财务项目详情：
- 新增任务管理 tab（月份/类型/数量/已执行/差额/单价/执行金额/未执行金额）
- 新增项目编号、开始/结束时间、项目经理、合同服务费标准(5%-25%下拉)
- 科普业务类型新增科普专访、患教会
- task_data JSON 存储任务列表

财务视图：
- 只保留总视图和月度视图，去除确收/毛利和回款/应付视图
- 月度视图月份选择器
- 表格统一居中对齐
- 去除流程项目/流程金额卡片

backend/migrations/columns.py

@@ -75,6 +75,24 @@ def migrate_add_columns():
         _add_column_if_missing(conn, "project_finances", "total_paid",
             "ALTER TABLE project_finances ADD COLUMN total_paid DOUBLE NOT NULL DEFAULT 0")
 
+        # project_finances 项目基本信息扩展字段
+        _add_column_if_missing(conn, "project_finances", "project_code",
+            "ALTER TABLE project_finances ADD COLUMN project_code VARCHAR(50) NOT NULL DEFAULT ''")
+        _add_column_if_missing(conn, "project_finances", "start_date",
+            "ALTER TABLE project_finances ADD COLUMN start_date VARCHAR(30) NOT NULL DEFAULT ''")
+        _add_column_if_missing(conn, "project_finances", "end_date",
+            "ALTER TABLE project_finances ADD COLUMN end_date VARCHAR(30) NOT NULL DEFAULT ''")
+        _add_column_if_missing(conn, "project_finances", "task_type",
+            "ALTER TABLE project_finances ADD COLUMN task_type VARCHAR(100) NOT NULL DEFAULT ''")
+        _add_column_if_missing(conn, "project_finances", "task_count",
+            "ALTER TABLE project_finances ADD COLUMN task_count DOUBLE NOT NULL DEFAULT 0")
+        _add_column_if_missing(conn, "project_finances", "service_fee_standard",
+            "ALTER TABLE project_finances ADD COLUMN service_fee_standard DOUBLE NOT NULL DEFAULT 0")
+        _add_column_if_missing(conn, "project_finances", "project_manager",
+            "ALTER TABLE project_finances ADD COLUMN project_manager VARCHAR(100) NOT NULL DEFAULT ''")
+        _add_column_if_missing(conn, "project_finances", "task_data",
+            "ALTER TABLE project_finances ADD COLUMN task_data TEXT")
+
         conn.commit()
         print("[migrate] 加列迁移完成")
     finally: