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/packages.sh

@@ -11,6 +11,38 @@ install_sunshine() {
   # Ensure runtime deps useful for capture/diagnostics across vendors.
   yay_install pipewire-pulse vulkan-tools libva-utils jq
   yay_install "$SUNSHINE_PKG"
+
+  # sunshine-bin is a precompiled AUR package; it breaks whenever Arch bumps a
+  # major shared library (most commonly ICU). Detect that and fall back to the
+  # source build, which links against whatever's currently installed.
+  if ! sunshine_runtime_deps_ok; then
+    if [[ "$SUNSHINE_PKG" == "sunshine-bin" ]]; then
+      warn "sunshine-bin has unresolved shared library deps (rolling-Arch library drift)."
+      warn "Falling back to the source build (AUR 'sunshine'). This takes ~5-10 minutes."
+      ldd "$(command -v sunshine)" 2>/dev/null | grep 'not found' | sed 's/^/    /' >&2 || true
+      as_root pacman -Rns --noconfirm sunshine-bin
+      SUNSHINE_PKG="sunshine"
+      yay_install sunshine
+      if ! sunshine_runtime_deps_ok; then
+        err "Source build also reports unresolved deps. Inspect: ldd \$(command -v sunshine)"
+        return 1
+      fi
+      ok "Recovered with source build"
+    else
+      err "sunshine binary has unresolved shared library deps:"
+      ldd "$(command -v sunshine)" 2>/dev/null | grep 'not found' | sed 's/^/    /' >&2 || true
+      err "Try: SUNSHINE_PKG=sunshine ./install.sh"
+      return 1
+    fi
+  fi
+}
+
+# True if every shared library sunshine links against resolves on this system.
+sunshine_runtime_deps_ok() {
+  local bin
+  bin="$(command -v sunshine 2>/dev/null || true)"
+  [[ -n "$bin" ]] || return 1
+  ! ldd "$bin" 2>/dev/null | grep -q 'not found'
 }
 
 install_moonlight() {

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 || {