新增订单收票付款交货跟进并完善使用升级手册

增加部分付款和部分交货状态、工作台筛选、权限校验、跟进记录及 v4 数据迁移；补充 Windows EXE 构建与验收脚本。附 16 页 PDF 使用升级手册及企业微信详细配置说明、生成脚本和测试截图。验证：76 项回归测试、EXE 浏览器验收与 PDF 逐页校验通过。

po_app/migrations.py

@@ -14,7 +14,7 @@ def upgrade_database(path):
         if 'orders' not in tables:
             return
         version = con.execute('PRAGMA user_version').fetchone()[0]
-        if version >= 3:
+        if version >= 4:
             return
         duplicates = con.execute('SELECT order_no, COUNT(*) FROM orders GROUP BY order_no HAVING COUNT(*) > 1').fetchall()
         if duplicates:
@@ -26,14 +26,35 @@ def upgrade_database(path):
         try:
             if version < 2:
                 upgrade_fixed_amounts(con)
-            merge_approval(con, tables)
-            con.execute('PRAGMA user_version=3')
+            if version < 3:
+                merge_approval(con, tables)
+            add_tracking(con)
+            con.execute('PRAGMA user_version=4')
             con.commit()
         except Exception:
             con.rollback()
             raise
 
 
+def add_tracking(con):
+    # Historical invoices, payments and deliveries are unknown until recorded.
+    additions = {
+        'needs_prepayment': 'BOOLEAN NOT NULL DEFAULT 0',
+        'invoice_status': "VARCHAR(20) NOT NULL DEFAULT 'unknown'",
+        'delivery_status': "VARCHAR(20) NOT NULL DEFAULT 'unknown'",
+        'payment_status': "VARCHAR(20) NOT NULL DEFAULT 'unknown'",
+        'payment_date': "VARCHAR(10) NOT NULL DEFAULT ''",
+        'fulfillment_note': "TEXT NOT NULL DEFAULT ''",
+        'payment_note': "TEXT NOT NULL DEFAULT ''",
+        'fulfillment_revision': 'INTEGER NOT NULL DEFAULT -1',
+        'payment_revision': 'INTEGER NOT NULL DEFAULT -1',
+    }
+    existing = {row[1] for row in con.execute('PRAGMA table_info(orders)')}
+    for name, definition in additions.items():
+        if name not in existing:
+            con.execute('ALTER TABLE orders ADD COLUMN %s %s' % (name, definition))
+
+
 def upgrade_fixed_amounts(con):
     additions = {
         'users': {'session_version': 'INTEGER NOT NULL DEFAULT 1', 'must_change_password': 'BOOLEAN NOT NULL DEFAULT 1'},