fix(sp7): mark ClaimDetail.lineReconciliation optional for back-compat

Existing test fixtures (ClaimDrawer, ClaimDrawerHeader, Claims pages)
construct partial ClaimDetail objects without the new slim
lineReconciliation projection. Other SP7 fields follow the optional
pattern (matchedLines?, serviceLinePayments?, claimLevelAdjustments?),
so apply the same to lineReconciliation.

Backend always emits it for matched claims; UI treats absent as
"no per-line audit yet".

src/types/index.ts

@@ -591,7 +591,7 @@ export interface ClaimDetail {
    * ``adjustmentsSum`` are null when the line has no matched 835 SVC
    * composite.
    */
-  lineReconciliation: ClaimDetailLineReconciliation[];
+  lineReconciliation?: ClaimDetailLineReconciliation[];
 }
 
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