feat: add TallyNote local reimbursement ledger

server/audit.ts

@@ -0,0 +1,39 @@
+import type Database from "better-sqlite3";
+
+export type AuditInput = {
+  requestId: string;
+  actorAdminId?: string | null;
+  actorUsername?: string | null;
+  action: string;
+  targetType: string;
+  targetId?: string | null;
+  outcome?: "success" | "denied" | "failure";
+  before?: unknown;
+  after?: unknown;
+  metadata?: unknown;
+};
+
+function json(value: unknown): string | null {
+  return value === undefined ? null : JSON.stringify(value);
+}
+
+export function writeAudit(sqlite: Database.Database, input: AuditInput): void {
+  sqlite.prepare(`
+    INSERT INTO audit_events (
+      occurred_at, request_id, actor_admin_id, actor_username, action,
+      target_type, target_id, outcome, before_json, after_json, metadata_json
+    ) VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
+  `).run(
+    Date.now(),
+    input.requestId,
+    input.actorAdminId ?? null,
+    input.actorUsername ?? null,
+    input.action,
+    input.targetType,
+    input.targetId ?? null,
+    input.outcome ?? "success",
+    json(input.before),
+    json(input.after),
+    json(input.metadata),
+  );
+}