Optimize installer: preflight checks, tuned conf, doctor, faster default

Layers a few things on top of the initial scaffold:

- Default to sunshine-bin (precompiled, ~seconds) instead of building from
  source. --from-source restores the old behavior.
- Add lib/preflight.sh: catches the gotchas before any work is done —
  Wayland session, NVIDIA driver responsive, nvidia-drm.modeset, amdgpu
  loaded, pipewire-pulse present, SSH-without-session warning.
- Add lib/config.sh: writes a tuned ~/.config/sunshine/sunshine.conf with
  per-vendor encoder settings (NVENC P1+ll+cbr, VAAPI ultralowlatency,
  QuickSync veryfast), KMS capture, pulse audio sink. Uses a
  "# managed-by: omarchy-moonlight" marker; removing it hands ownership
  back to the user and the installer won't touch the file again.
- Add lib/verify.sh: post-install verification of every step
  (cap_sys_admin set, group resolves, udev rule present, /dev/uinput
  exists, encoder reachable, service active, :47990 listening). Same
  checks are reachable standalone via --doctor.
- Install runtime helpers (pipewire-pulse, vulkan-tools, libva-utils)
  alongside Sunshine for diagnostics + audio.
- Uninstall handles both sunshine + sunshine-bin and the -bin moonlight
  variant.
- README documents the tuning table, the new flags, and the modeset
  troubleshooting path.

install.sh

@@ -10,14 +10,20 @@ SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
 source "$SCRIPT_DIR/lib/common.sh"
 # shellcheck source=lib/detect.sh
 source "$SCRIPT_DIR/lib/detect.sh"
+# shellcheck source=lib/preflight.sh
+source "$SCRIPT_DIR/lib/preflight.sh"
 # shellcheck source=lib/packages.sh
 source "$SCRIPT_DIR/lib/packages.sh"
 # shellcheck source=lib/permissions.sh
 source "$SCRIPT_DIR/lib/permissions.sh"
+# shellcheck source=lib/config.sh
+source "$SCRIPT_DIR/lib/config.sh"
 # shellcheck source=lib/firewall.sh
 source "$SCRIPT_DIR/lib/firewall.sh"
 # shellcheck source=lib/service.sh
 source "$SCRIPT_DIR/lib/service.sh"
+# shellcheck source=lib/verify.sh
+source "$SCRIPT_DIR/lib/verify.sh"
 
 usage() {
   cat <<EOF
@@ -30,11 +36,14 @@ Options:
   --no-firewall     Skip firewall configuration
   --no-moonlight    Don't install moonlight-qt (host-only setup)
   --no-sunshine     Don't install sunshine (client-only setup)
+  --no-config       Don't write a tuned sunshine.conf
+  --from-source     Build Sunshine from source (equivalent to SUNSHINE_PKG=sunshine)
+  --doctor          Run only the post-install verification checks
   -h, --help        Show this help
 
 Environment overrides:
-  SUNSHINE_PKG       AUR package to use for Sunshine (default: sunshine)
-                     Set to 'sunshine-bin' for the precompiled build.
+  SUNSHINE_PKG       AUR package to use for Sunshine (default: sunshine-bin)
+                     Set to 'sunshine' to build from source instead.
 EOF
 }
 
@@ -42,6 +51,8 @@ AUTOSTART=1
 FIREWALL=1
 INSTALL_SUNSHINE=1
 INSTALL_MOONLIGHT=1
+WRITE_CONFIG=1
+DOCTOR_ONLY=0
 
 while [[ $# -gt 0 ]]; do
   case "$1" in
@@ -49,6 +60,9 @@ while [[ $# -gt 0 ]]; do
     --no-firewall)   FIREWALL=0 ;;
     --no-moonlight)  INSTALL_MOONLIGHT=0 ;;
     --no-sunshine)   INSTALL_SUNSHINE=0 ;;
+    --no-config)     WRITE_CONFIG=0 ;;
+    --from-source)   export SUNSHINE_PKG=sunshine ;;
+    --doctor)        DOCTOR_ONLY=1 ;;
     -h|--help)       usage; exit 0 ;;
     *)               err "Unknown option: $1"; usage; exit 2 ;;
   esac
@@ -64,6 +78,14 @@ main() {
   detect_all
   info "Host: $HOSTNAME_SHORT   GPU: $GPU_VENDOR   Session: $SESSION_TYPE"
 
+  if [[ $DOCTOR_ONLY -eq 1 ]]; then
+    verify_install
+    exit $(( VERIFY_FAILURES > 0 ? 1 : 0 ))
+  fi
+
+  step "Preflight checks"
+  preflight_all
+
   if [[ $INSTALL_SUNSHINE -eq 1 ]]; then
     step "Installing Sunshine and GPU encoder support"
     install_sunshine
@@ -74,6 +96,13 @@ main() {
     ensure_uinput_udev_rule
     set_sunshine_capabilities
 
+    if [[ $WRITE_CONFIG -eq 1 ]]; then
+      step "Writing tuned sunshine.conf"
+      write_sunshine_config
+    else
+      info "Skipping sunshine.conf (--no-config)"
+    fi
+
     if [[ $FIREWALL -eq 1 ]]; then
       step "Configuring firewall for Sunshine ports"
       open_sunshine_ports
@@ -98,6 +127,10 @@ main() {
     info "Skipping Moonlight install (--no-moonlight)"
   fi
 
+  if [[ $INSTALL_SUNSHINE -eq 1 ]]; then
+    verify_install
+  fi
+
   step "Done"
   print_next_steps
 }