Implement dashboard and audit log templates, add paginated audit log support

- Added `web/templates/{dashboard,audit,base,accounts,account_detail}.html` for a consistent UI.
- Implemented new audit log endpoint (`GET /v1/audit`) with filtering and pagination via `ListAuditEventsPaged`.
- Extended `AuditQueryParams`, added `AuditEventView` for joined actor/target usernames.
- Updated configuration (`goimports` preference), linting rules, and E2E tests.
- No logic changes to existing APIs.

test/e2e/e2e_test.go

@@ -514,8 +514,8 @@ func TestE2ESystemAccountTokenIssuance(t *testing.T) {
 	resp3 := e.do(t, "POST", "/v1/token/validate", nil, tokenResp.Token)
 	mustStatus(t, resp3, http.StatusOK)
 	var vr struct {
-		Valid   bool   `json:"valid"`
 		Subject string `json:"sub"`
+		Valid   bool   `json:"valid"`
 	}
 	decodeJSON(t, resp3, &vr)
 	if !vr.Valid {