feat(server): expose marks_as_test on InviteCode

Adds the field to the dataclass, SELECT list in get_invite_codes,
and a new get_invite_code_details helper that the register flow
will use to discover whether an invite should flag new accounts
as test accounts.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

server/services/admin_service.py

@@ -123,6 +123,7 @@ class InviteCode:
     max_uses: int
     use_count: int
     is_active: bool
+    marks_as_test: bool = False
 
     def to_dict(self) -> dict:
         return {
@@ -135,6 +136,7 @@ class InviteCode:
             "use_count": self.use_count,
             "is_active": self.is_active,
             "remaining_uses": max(0, self.max_uses - self.use_count),
+            "marks_as_test": self.marks_as_test,
         }
 
 
@@ -1117,6 +1119,7 @@ class AdminService:
             query = """
                 SELECT c.code, c.created_by, c.created_at, c.expires_at,
                        c.max_uses, c.use_count, c.is_active,
+                       COALESCE(c.marks_as_test, FALSE) as marks_as_test,
                        u.username as created_by_username
                 FROM invite_codes c
                 JOIN users_v2 u ON c.created_by = u.id
@@ -1138,6 +1141,7 @@ class AdminService:
                     max_uses=row["max_uses"],
                     use_count=row["use_count"],
                     is_active=row["is_active"],
+                    marks_as_test=row["marks_as_test"],
                 )
                 for row in rows
             ]
@@ -1213,6 +1217,34 @@ class AdminService:
 
             return True
 
+    async def get_invite_code_details(self, code: str) -> Optional[dict]:
+        """
+        Look up an invite code's row including marks_as_test.
+
+        Returns None if the code does not exist. Does NOT validate expiry
+        or usage — use validate_invite_code for that. This is purely a
+        helper for the register flow to discover the test-seed flag.
+        """
+        async with self.pool.acquire() as conn:
+            row = await conn.fetchrow(
+                """
+                SELECT code, max_uses, use_count, is_active,
+                       COALESCE(marks_as_test, FALSE) as marks_as_test
+                FROM invite_codes
+                WHERE code = $1
+                """,
+                code,
+            )
+            if not row:
+                return None
+            return {
+                "code": row["code"],
+                "max_uses": row["max_uses"],
+                "use_count": row["use_count"],
+                "is_active": row["is_active"],
+                "marks_as_test": row["marks_as_test"],
+            }
+
     async def use_invite_code(self, code: str) -> bool:
         """
         Use an invite code (increment use count).