refactor(server): 单号规则收紧为 A/R/D+8 位紧凑格式

- DOCUMENT_NUMBER_PREFIXES 改为 A/R/D，新增短格式与旧格式正则并存识别，提取正则加边界锚定避免误匹配
- build_document_number 去掉时间戳段，统一生成 A+token 等紧凑单号，is_application_claim_no 兼容旧 AP-/APP- 前缀
- access_policy/status_registry/reimbursements/expense_claims/budget_support 统一复用 is_application_claim_no 判定申请单
- 同步 document_numbering 单元测试覆盖新旧两种格式

server/src/app/services/expense_claim_status_registry.py

@@ -14,6 +14,7 @@ from app.services.expense_claim_workflow_constants import (
     PAYMENT_PAID_STAGE,
     PAYMENT_PENDING_STAGE,
 )
+from app.services.document_numbering import is_application_claim_no
 
 
 @dataclass(frozen=True, slots=True)
@@ -158,7 +159,7 @@ def is_application_claim_reference(
     normalized_no = str(claim_no or "").strip().upper()
     normalized_type = str(expense_type or "").strip().lower()
     return (
-        normalized_no.startswith(("AP-", "APP-"))
+        is_application_claim_no(normalized_no)
         or normalized_type == "application"
         or normalized_type.endswith("_application")
     )