Auto-recover from sunshine-bin library drift; reset-failed before service start

Two robustness fixes for failures hit on a real install.

lib/packages.sh
- After installing $SUNSHINE_PKG, run ldd against the binary and check for
  "not found" entries. sunshine-bin ships against whichever ICU was current
  at AUR-build time; on rolling Arch (jarvis is on ICU 78, package built
  against ICU 76) this leaves libicuuc.so.76 unresolved and sunshine exits
  127 on every start, eventually tripping the systemd start-limit.
- If sunshine-bin has unresolved deps, remove it and fall back to the
  source build (AUR 'sunshine'), then re-verify. If the user explicitly
  chose --from-source and it still fails, bail with the ldd diagnostic.

lib/service.sh
- systemctl --user reset-failed before restart, so a previous attempt that
  hit start-limit-hit doesn't immediately reject the new start request.
  (Re-running install.sh after a broken first attempt was failing because
  systemd remembered the prior rate-limit trip.)

lib/service.sh

@@ -18,6 +18,10 @@ enable_sunshine_service() {
   info "Enabling sunshine.service (user)"
   systemctl --user enable sunshine.service >/dev/null
 
+  # Clear any prior start-limit state from a failed run so this attempt isn't
+  # immediately rejected with "Start request repeated too quickly."
+  systemctl --user reset-failed sunshine.service 2>/dev/null || true
+
   info "Starting sunshine.service (user)"
   # Restart so a re-run picks up new config / new caps. Tolerate first-launch races.
   systemctl --user restart sunshine.service || systemctl --user start sunshine.service || {