Add gSlapper video wallpaper plugin (#152)

* feat: add gSlapper wallpaper plugin

* docs: clarify gSlapper installation and testing

* docs: state Noctalia v5 requirement

* docs: use generated plugin thumbnail

* fix: keep gSlapper videos playing by default

gslapper/widget.luau

@@ -0,0 +1,18 @@
+--!nonstrict
+
+local PANEL_ID = "nomadcxx/gslapper:picker"
+
+local function render()
+  barWidget.setGlyph(noctalia.getConfig("glyph") or "wallpaper-selector")
+  barWidget.setTooltip(noctalia.tr("widget.tooltip"))
+end
+
+function onClick()
+  noctalia.togglePanel(PANEL_ID)
+end
+
+function onConfigChanged()
+  render()
+end
+
+render()