changeIp() rebuilt the warp outbound from a fixed default template via
collectConfig and replaced the whole in-memory object through
onResetOutbound, so only secretKey/address/reserved and the first peer's
publicKey/endpoint survived — a user's custom mtu, domainStrategy,
noKernelTun, the first peer's keepAlive / allowedIPs / preSharedKey, and
any extra peers were silently dropped from the editor. Because the page
keeps rendering that in-memory copy and a later page Save persists it to
/panel/api/xray/update, the loss could become permanent, even though the
backend ChangeWarpIP already patches only the rotated fields and leaves
everything else intact in the stored template.
Mirror the server-side UpdateWarpXraySetting: merge only the rotated
fields (secretKey, address, reserved, first peer publicKey/endpoint)
into the existing outbound, preserving the rest. register() (first-time
creation, nothing to preserve) still uses collectConfig's full build.
Extracted as a pure module-level mergeWarpRotation so it is unit-testable
without rendering the modal.
Fixes#6019
H-TTTTT