DKR-R 1.0.9 - Rollback connection check playtest 8
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The connection check now follows Rollback instead of grading the old online
modes. Open DKR-R Online, join a lobby together, then the host can select
"Check Rollback connection". Everyone should use this updated build.

It takes about ten seconds: two to negotiate support, six to measure, two to
wait for the final replies. You can leave the Online page open or switch to
another launcher page; the network worker owns the check, not the UI.

Racers use synthetic 30 Hz input probes on the same delivery class as their
Rollback backend: Control in spectator-capable lobbies, Realtime in ordinary
lobbies. Ordinary lobbies also check the Authoritative repair channel at 20 Hz.
Spectators are checked separately using 20 Hz Replica probes. They never take
a controller slot, stall the racers or lower a racer's timing assessment.
Checkpoint-channel readiness is checked, not full checkpoint throughput.

The report shows median/p95 round-trip timing, RTT variation, missing replies,
transport queues, local probe-scheduling delays, and conservative headroom
against the selected input delay / prediction window at 30 Hz. Recommendations
use the existing Rollback automatic-delay formula, with two prediction frames
reserved and its existing 8 ms margin. No settings are changed automatically.

These are authenticated synthetic probes, not real game inputs. Missing probe
replies are not gameplay packet-loss measurements. RTT is not measured one-way
latency. This is not a bandwidth benchmark or a guarantee of FPS or game sync.
Unsupported clients and insufficient samples are reported as inconclusive,
not assigned a guessed old ten-point score. The host sees each participant;
updated clients receive the host's report for their own connection.

Changing the lobby membership, roles, settings or launch state invalidates the
report. Starting a game cancels the check. Probe traffic is bounded, is never
queued behind the game's reliable messages and stops during gameplay.

The existing restored lobby, invites, vehicle/mod features and accepted
upstream fixes are retained. No race simulation or rendering code is changed.

VALIDATION
Compilation/linking and static source/binary/archive inspection only. No game,
mod, test executable or AppImage has been launched. Gameplay and real-network
validation remain yours. Nothing has been published, pushed or update-signed.
