feat(batch-diff): side-by-side claim diff between two batches

src/types/index.ts

@@ -560,3 +560,79 @@ export interface ClaimDetail {
   matchedRemittance: ClaimDetailMatchedRemittance | null;
   stateHistory: ClaimDetailStateHistoryEvent[];
 }
+
+// ---------------------------------------------------------------------------
+// Side-by-side batch diff (SP3 P4 / T18)
+// Mirrors `GET /api/batch-diff?a=<batch_id>&b=<batch_id>` (see
+// `backend/src/cyclone/batch_diff.py` and `backend/src/cyclone/api.py`).
+// The contract is deliberately small: no raw segments, no service-line
+// details — just the summary fields the operator needs to spot the
+// deltas between two parsed files at a glance.
+// ---------------------------------------------------------------------------
+
+export type BatchKind = "837p" | "835";
+
+export interface BatchDiffSideMeta {
+  id: string;
+  kind: BatchKind;
+  parsedAt: string; // ISO Z
+  inputFilename: string;
+  claimCount: number;
+}
+
+/**
+ * One claim (or remittance) row projected for the diff view. Carries
+ * just enough context to render side-by-side without the EDI parse
+ * tree. ``status`` carries the validation-derived label for 837P
+ * (``submitted`` / ``pending`` / ``draft`` / ``denied``) and the CLP02
+ * code/label for 835.
+ */
+export interface BatchClaimDiffSummary {
+  claim_id: string;
+  patient_name: string;
+  total_charge: number;
+  service_date: string | null;
+  status: string;
+  cpt_codes: string[];
+}
+
+/**
+ * One changed field between the two sides of a claim. ``field``
+ * identifies which column changed (``status`` / ``total_charge`` /
+ * ``service_date`` / ``cpt_codes``); ``a`` and ``b`` are the values
+ * from each side, rendered verbatim.
+ */
+export interface BatchDiffFieldDiff {
+  field: "status" | "total_charge" | "service_date" | "cpt_codes";
+  a: string | number | string[] | null;
+  b: string | number | string[] | null;
+}
+
+export interface BatchDiffChangedRow {
+  a: BatchClaimDiffSummary;
+  b: BatchClaimDiffSummary;
+  diff: BatchDiffFieldDiff[];
+}
+
+export interface BatchDiffSummary {
+  addedCount: number;
+  removedCount: number;
+  changedCount: number;
+  unchangedCount: number;
+}
+
+/**
+ * Full response from `GET /api/batch-diff`. The three bucket arrays
+ * (``added`` / ``removed`` / ``changed``) are always present (never
+ * absent) so the UI can index unconditionally; ``summary`` is
+ * precomputed by the backend so the four count cards don't have to
+ * derive them on the client.
+ */
+export interface BatchDiff {
+  a: BatchDiffSideMeta;
+  b: BatchDiffSideMeta;
+  added: BatchClaimDiffSummary[];
+  removed: BatchClaimDiffSummary[];
+  changed: BatchDiffChangedRow[];
+  summary: BatchDiffSummary;
+}