DKR-R v1.0.9 - Spectators Playtest 4

ONE ONLINE MODE: ROLLBACK

Online play now uses Rollback. That's the same owned replay engine previously
called Experimental Rollback, not the older Host Prediction implementation.
The mode dropdown, Auto, Host Prediction and Strict Input Sync choices have
been removed. There is no automatic fallback to a different sync engine.

Host settings start with:
  Spectator-capable lobby: on
  Menu control: host until character select
  Maximum players: 4
  Prediction window: 14 frames
  Automatic input delay: off
  Input delay: 6 frames
  Record game replay: off
  Development lobby: off

You can still adjust the remaining settings. These are defaults, not locked
values. Existing valid timing/player preferences are kept. Missing or invalid
settings use the new defaults. Old saved backend choices always migrate to
Rollback; the other sync modes cannot be re-enabled through the settings file.

Development lobby remains available for modders, but is off by default. If
you turn it on, racers must consent to host tool commands, progress remains
temporary and achievements are paused. Turning it off does not delete saves.

Everyone in the lobby needs this exact build. Older or unsupported sync modes
are rejected, never silently treated as Rollback. Install the complete package
if the Rollback adapter is unavailable. Do not copy only the runtime binary.

SPECTATORS, SWAPS AND INVITATIONS

Host settings still control whether spectators are allowed. Up to four racers
and eight spectators can share a spectator-capable lobby. Watchers do not get
controller ports. Spectators can choose all splits, follow a racer or use the
T.T.-style director. Racer/spectator swaps still require host approval and an
agreed confirmed handover. The host must remain connected; no host migration.

Lobby invites have Accept, Decline and Later buttons. Use the normal Open /
Close DKR-R Menu shortcut to respond with a controller. Accepting during a
game asks before leaving, stops normally, returns to the launcher and joins.
Already-saved progress is kept; this does not save your position in a race.
Local multiplayer stops for everyone on that machine. Host departure closes
the old lobby. Save/shutdown errors prevent joining the new lobby.

Later hides the toast but leaves the invitation in the online invitation list.
Decline tells the sender you're not joining. The destination host still
controls spectator admission. Mod downloads and code permissions are unchanged.

YOUR CHECKLIST

Check a fresh settings profile and an existing profile. Confirm the defaults,
change delay/window values, restart, then confirm your choices remain. Check
that Development lobby is off for a fresh profile. An existing explicit choice
to use a Development lobby is retained; switch it off for ordinary progress.

Try Windows/Linux hosting, 2/3/4 racers, spectators, swaps, friend invites,
manual joins and modded lobbies. Check both ROM revisions if available. Keep
the host/client runtime.log files if anything goes wrong.

Compiled and statically inspected only. The coding agent did not launch the
game, mods, tests or AppImage. Gameplay testing is yours. This is an unpublished
playtest, not a production release or a signed automatic update.
