feat: 统一后端分页查询与前端服务层适配

后端新增通用分页模块，为报销单、员工、预算、agent 资产等
端点统一接入分页参数和游标查询，优化 repository 层分页实
现，前端服务层适配分页响应结构，完善预算图表和全局样式，
优化侧边栏和企业选择器组件，引入 Element Plus 插件注册。

server/src/app/api/v1/endpoints/reimbursements.py

@@ -7,8 +7,9 @@ from fastapi.responses import FileResponse
 from sqlalchemy.orm import Session
 
 from app.api.deps import CurrentUserContext, get_current_user, get_db
+from app.api.pagination import PageNumber, PageSize, page_payload, wants_page
 from app.schemas.budget import BudgetClaimAnalysisRead
-from app.schemas.common import ErrorResponse
+from app.schemas.common import ErrorResponse, PaginatedResponse
 from app.schemas.reimbursement import (
     ExpenseClaimAttachmentActionResponse,
     ExpenseClaimActionResponse,
@@ -25,8 +26,8 @@ from app.schemas.reimbursement import (
     TravelReimbursementCalculatorRequest,
     TravelReimbursementCalculatorResponse,
 )
-from app.services.expense_claims import ExpenseClaimService
 from app.services.budget import BudgetService
+from app.services.expense_claims import ExpenseClaimService
 from app.services.reimbursement import ReimbursementService
 from app.services.travel_reimbursement_calculator import TravelReimbursementCalculatorService
 
@@ -37,12 +38,19 @@ CurrentUser = Annotated[CurrentUserContext, Depends(get_current_user)]
 
 @router.get(
     "",
-    response_model=list[ReimbursementRead],
+    response_model=list[ReimbursementRead] | PaginatedResponse[ReimbursementRead],
     summary="查询报销申请列表",
     description="返回当前系统中的报销申请列表。",
 )
-def list_reimbursements(db: DbSession) -> list[ReimbursementRead]:
-    return ReimbursementService(db).list_reimbursements()
+def list_reimbursements(
+    db: DbSession,
+    page: PageNumber = None,
+    page_size: PageSize = None,
+) -> list[ReimbursementRead] | PaginatedResponse[ReimbursementRead]:
+    service = ReimbursementService(db)
+    if wants_page(page, page_size):
+        return page_payload(service.list_reimbursements_page(page=page, page_size=page_size))
+    return service.list_reimbursements()
 
 
 @router.post(
@@ -81,32 +89,60 @@ def calculate_travel_reimbursement(
 
 @router.get(
     "/claims",
-    response_model=list[ExpenseClaimRead],
+    response_model=list[ExpenseClaimRead] | PaginatedResponse[ExpenseClaimRead],
     summary="查询个人报销单列表",
     description="返回当前登录用户可见的真实个人报销单据列表。",
 )
-def list_expense_claims(db: DbSession, current_user: CurrentUser) -> list[ExpenseClaimRead]:
-    return ExpenseClaimService(db).list_claims(current_user)
+def list_expense_claims(
+    db: DbSession,
+    current_user: CurrentUser,
+    page: PageNumber = None,
+    page_size: PageSize = None,
+) -> list[ExpenseClaimRead] | PaginatedResponse[ExpenseClaimRead]:
+    service = ExpenseClaimService(db)
+    if wants_page(page, page_size):
+        return page_payload(service.list_claims_page(current_user, page=page, page_size=page_size))
+    return service.list_claims(current_user)
 
 
 @router.get(
     "/claims/approvals",
-    response_model=list[ExpenseClaimRead],
+    response_model=list[ExpenseClaimRead] | PaginatedResponse[ExpenseClaimRead],
     summary="查询当前用户审批待办报销单列表",
     description="返回当前登录用户有权处理的待审批报销单据，不混入个人报销列表。",
 )
-def list_expense_claim_approvals(db: DbSession, current_user: CurrentUser) -> list[ExpenseClaimRead]:
-    return ExpenseClaimService(db).list_approval_claims(current_user)
+def list_expense_claim_approvals(
+    db: DbSession,
+    current_user: CurrentUser,
+    page: PageNumber = None,
+    page_size: PageSize = None,
+) -> list[ExpenseClaimRead] | PaginatedResponse[ExpenseClaimRead]:
+    service = ExpenseClaimService(db)
+    if wants_page(page, page_size):
+        return page_payload(
+            service.list_approval_claims_page(current_user, page=page, page_size=page_size)
+        )
+    return service.list_approval_claims(current_user)
 
 
 @router.get(
     "/claims/archives",
-    response_model=list[ExpenseClaimRead],
+    response_model=list[ExpenseClaimRead] | PaginatedResponse[ExpenseClaimRead],
     summary="查询归档中心报销单列表",
     description="返回公司已归档入账的报销单据，供财务与审计角色集中查阅。",
 )
-def list_archived_expense_claims(db: DbSession, current_user: CurrentUser) -> list[ExpenseClaimRead]:
-    return ExpenseClaimService(db).list_archived_claims(current_user)
+def list_archived_expense_claims(
+    db: DbSession,
+    current_user: CurrentUser,
+    page: PageNumber = None,
+    page_size: PageSize = None,
+) -> list[ExpenseClaimRead] | PaginatedResponse[ExpenseClaimRead]:
+    service = ExpenseClaimService(db)
+    if wants_page(page, page_size):
+        return page_payload(
+            service.list_archived_claims_page(current_user, page=page, page_size=page_size)
+        )
+    return service.list_archived_claims(current_user)
 
 
 @router.get(