feat(approvals): Approval Flow v2 프런트엔드 전면 개편

- 환경/라우터 모듈에 approval_flow_v2 토글을 추가하고 FeatureFlags 초기화를 연결 (.env*, lib/core/**)
- ApiClient 빌더·ApiRoutes 확장과 ApprovalRepositoryRemote 리팩터링으로 include·액션 시그니처를 정합화
- ApprovalFlow·ApprovalDraft 엔티티/레포/유즈케이스를 도입해 서버 초안과 단계 액션(승인·회수·재상신)을 지원
- Approval 컨트롤러·히스토리·템플릿 페이지와 공유 위젯을 재작성해 감사 로그·회수 UX·템플릿 CRUD를 반영
- Inbound/Outbound/Rental 컨트롤러·페이지에 결재 섹션을 삽입하고 대시보드 pending 카드 요약을 갱신
- SuperportDialog·FormField 등 공통 위젯을 보강하고 승인 위젯 가이드를 추가해 UI 가이드를 정리
- 결재/재고 테스트 픽스처와 단위·위젯·통합 테스트를 확장하고 flutter_test_config로 스테이징 호스트를 허용
- Approval Flow 레포트/플랜 문서를 업데이트하고 ApprovalFlow_System_Integration_and_ChangePlan.md를 추가
- 실행: flutter analyze, flutter test

test/fixtures/approvals/approval_five_step_pending.json

@@ -0,0 +1,237 @@
+{
+  "id": 51001,
+  "approval_no": "APP-202511100201",
+  "transaction": {
+    "id": 91001,
+    "transaction_no": "IN-20251110-0001"
+  },
+  "status": {
+    "id": 2,
+    "name": "진행중",
+    "color": "#3B82F6",
+    "is_blocking_next": true,
+    "is_terminal": false
+  },
+  "current_step": {
+    "id": 72003,
+    "step_order": 3,
+    "status": {
+      "id": 2,
+      "name": "진행중",
+      "is_blocking_next": true,
+      "is_terminal": false
+    },
+    "approver": {
+      "id": 104,
+      "employee_id": "E20250104",
+      "employee_no": "E20250104",
+      "name": "박팀장"
+    },
+    "assigned_at": "2025-09-18T07:10:00Z",
+    "decided_at": null,
+    "note": null
+  },
+  "requester": {
+    "id": 77,
+    "employee_id": "E20250077",
+    "employee_no": "E20250077",
+    "name": "김상신"
+  },
+  "requested_at": "2025-09-18T06:55:00Z",
+  "decided_at": null,
+  "note": "입고 5단계 결재",
+  "is_active": true,
+  "is_deleted": false,
+  "steps": [
+    {
+      "id": 72001,
+      "step_order": 1,
+      "status": {
+        "id": 3,
+        "name": "승인",
+        "is_blocking_next": false,
+        "is_terminal": false
+      },
+      "approver": {
+        "id": 101,
+        "employee_id": "E20250101",
+        "employee_no": "E20250101",
+        "name": "이검토"
+      },
+      "assigned_at": "2025-09-18T06:58:00Z",
+      "decided_at": "2025-09-18T06:59:30Z",
+      "note": "조건부 승인"
+    },
+    {
+      "id": 72002,
+      "step_order": 2,
+      "status": {
+        "id": 3,
+        "name": "승인",
+        "is_blocking_next": false,
+        "is_terminal": false
+      },
+      "approver": {
+        "id": 102,
+        "employee_id": "E20250102",
+        "employee_no": "E20250102",
+        "name": "최검수"
+      },
+      "assigned_at": "2025-09-18T07:00:00Z",
+      "decided_at": "2025-09-18T07:04:10Z",
+      "note": null
+    },
+    {
+      "id": 72003,
+      "step_order": 3,
+      "status": {
+        "id": 2,
+        "name": "진행중",
+        "is_blocking_next": true,
+        "is_terminal": false
+      },
+      "approver": {
+        "id": 104,
+        "employee_id": "E20250104",
+        "employee_no": "E20250104",
+        "name": "박팀장"
+      },
+      "assigned_at": "2025-09-18T07:10:00Z",
+      "decided_at": null,
+      "note": null
+    },
+    {
+      "id": 72004,
+      "step_order": 4,
+      "status": {
+        "id": 1,
+        "name": "대기",
+        "is_blocking_next": true,
+        "is_terminal": false
+      },
+      "approver": {
+        "id": 105,
+        "employee_id": "E20250105",
+        "employee_no": "E20250105",
+        "name": "정차장"
+      },
+      "assigned_at": "2025-09-18T07:10:00Z",
+      "decided_at": null,
+      "note": null
+    },
+    {
+      "id": 72005,
+      "step_order": 5,
+      "status": {
+        "id": 1,
+        "name": "대기",
+        "is_blocking_next": true,
+        "is_terminal": false
+      },
+      "approver": {
+        "id": 201,
+        "employee_id": "E20250201",
+        "employee_no": "E20250201",
+        "name": "한임원"
+      },
+      "assigned_at": "2025-09-18T07:10:00Z",
+      "decided_at": null,
+      "note": null
+    }
+  ],
+  "histories": [
+    {
+      "id": 93001,
+      "action": {
+        "id": 1,
+        "name": "상신"
+      },
+      "from_status": null,
+      "to_status": {
+        "id": 1,
+        "name": "대기",
+        "is_blocking_next": true,
+        "is_terminal": false
+      },
+      "approver": {
+        "id": 77,
+        "employee_id": "E20250077",
+        "employee_no": "E20250077",
+        "name": "김상신"
+      },
+      "action_at": "2025-09-18T06:55:00Z",
+      "note": null
+    },
+    {
+      "id": 93002,
+      "action": {
+        "id": 2,
+        "name": "승인"
+      },
+      "from_status": {
+        "id": 1,
+        "name": "대기",
+        "is_blocking_next": true,
+        "is_terminal": false
+      },
+      "to_status": {
+        "id": 3,
+        "name": "승인",
+        "is_blocking_next": false,
+        "is_terminal": false
+      },
+      "approver": {
+        "id": 101,
+        "employee_id": "E20250101",
+        "employee_no": "E20250101",
+        "name": "이검토"
+      },
+      "action_at": "2025-09-18T06:59:30Z",
+      "note": "조건 수용"
+    },
+    {
+      "id": 93003,
+      "action": {
+        "id": 2,
+        "name": "승인"
+      },
+      "from_status": {
+        "id": 1,
+        "name": "대기",
+        "is_blocking_next": true,
+        "is_terminal": false
+      },
+      "to_status": {
+        "id": 3,
+        "name": "승인",
+        "is_blocking_next": false,
+        "is_terminal": false
+      },
+      "approver": {
+        "id": 102,
+        "employee_id": "E20250102",
+        "employee_no": "E20250102",
+        "name": "최검수"
+      },
+      "action_at": "2025-09-18T07:04:10Z",
+      "note": null
+    }
+  ],
+  "created_at": "2025-09-18T06:55:00Z",
+  "updated_at": "2025-09-18T07:10:00Z",
+  "visibility": {
+    "allowed_roles": [
+      "requester",
+      "completed_approver"
+    ],
+    "restricted_roles": [
+      "pending_approver",
+      "external"
+    ]
+  },
+  "permissions": {
+    "can_recall": true,
+    "can_resubmit": false,
+    "can_comment": true
+  }
+}