docs: logi-wheel rename and 0.20.0 app improvements
Rename every reference to the settings app: logi-dd -> logi-wheel,
logi-dd-gui -> logi-wheel-gui, the crates and the userspace/logi-dd
workspace path, the config directory and the LOGI_DD_* env vars, plus the
screenshot filenames. logi-ffb and logi-tf-sim are unchanged.
Installation gains a short rename section (in-place package upgrade,
transitional symlinks, one-time config copy); Troubleshooting and the G923
page each point at it. Building and Contributing documents the deprecated
LOGI_DD_* aliases once.
Fold in the app changes: Info / Testing is the startup page and names the
wheel with its serial and firmware, settings a wheel lacks are hidden,
desktop profiles work without onboard slots, gain and autocenter show as
percent while sysfs stays raw, views scroll with a scrollbar, and the force
and TrueForce self-tests are full multi-step sequences with a plan and
per-step countdown (friction is skipped on a G923). Button Reference gains
the G923's captured 18-button table.
Also correct three stale claims against the repo: settings writes need the
udev rule, not the input group; the rev-light feeder runs at ~60 Hz, not
~160 ms; and simulated TrueForce covers F1, EA Sports WRC, BeamNG and the
relay listener.
docs: G923 support for 0.20.0
New G923 page (both editions, recipes, coexistence). Scope the
PROTON_ENABLE_HIDRAW / TrueForce-file advice to the RS50 / G PRO,
add the G923 classic sysfs section, simulated-TrueForce coverage,
install and troubleshooting rows, and refresh stale G920/G923
claims on Home, Architecture, Protocol Specification and
Building and Contributing.