feat: a tile that opens Lutris itself

`defineLibraryPlugin` has taken a `launchers()` hook since kit 0.3.0 — entries that
open the LAUNCHER rather than a title (design D4) — and nothing implemented it. The
host has resolved `launcher_ui` valued `"lutris"` since the same release. So the
whole path existed end to end with no producer at either end.

One entry, config-toggled and on by default: it is the one tile that lets someone
install or fix a game from the couch, and it costs a single card.

`launcher_ui` is valued by STORE ID, never a command: the host turns "lutris" into
the command that opens the window (D1). That is also the only shape available to a
plugin at all — the 2026-08-05 review made `launch.kind = "command"` operator-only,
so a plugin publishing one has its entire reconcile refused.

Deliberately art-less. Lutris ships a square app icon and every client cover-crops a
2:3 tile, so an icon would arrive as a cropped strip. The clients render an art-less
launcher entry on purpose — accent face, the launcher named — which reads as "opens
Lutris" rather than as a game whose poster failed to load.

`launcherEntries` is exported for the same reason `artFile` is: so the shape is
testable without standing up the whole plugin.

Gates: tsc --noEmit clean, 5 tests pass (2 new), biome clean.
Needs a host carrying the M2 wire (`role` + `launcher_ui`), which is on main.

src/plugin.ts

@@ -38,6 +38,20 @@ const LutrisConfig = Schema.Struct({
 				"Absolute path to pga.db. Leave empty to find it automatically.",
 		}),
 	),
+	/**
+	 * Publish a tile that opens the Lutris window itself (design D4) alongside the games. On by
+	 * default: it is the one entry that lets someone install or fix a game from the couch, and it
+	 * costs one tile.
+	 */
+	launcher: Schema.Boolean.annotate({
+		title: "Show a Lutris tile",
+		description:
+			"Add a tile that opens Lutris itself, so you can manage games from a client.",
+	}).pipe(
+		Schema.withDecodingDefaultKey(Effect.succeed(true), {
+			encodingStrategy: "omit",
+		}),
+	),
 });
 
 /** Candidate `pga.db` locations: XDG data dir, the classic path, Flatpak. */
@@ -99,6 +113,36 @@ interface GameRow {
 	directory: string | null;
 }
 
+/**
+ * The tile that opens Lutris itself (design D4).
+ *
+ * `launcher_ui` is valued by *store id*, never a command: the host owns turning "lutris" into
+ * the command that opens the window (D1), which is also why a plugin may publish this at all —
+ * the 2026-08-05 review made `launch.kind = "command"` operator-only.
+ *
+ * No art on purpose. Lutris ships a square app icon, and every client cover-crops a 2:3 tile,
+ * so an icon would arrive as a cropped strip. The clients render an art-less launcher entry
+ * deliberately — accent face, the launcher named — which reads as "opens Lutris" rather than as
+ * a game whose poster failed.
+ *
+ * A standalone exported function so it is testable without standing up the whole plugin —
+ * the same reason `artFile` is exported.
+ */
+export const launcherEntries = (cfg: {
+	launcher?: boolean;
+}): ProviderEntry[] =>
+	cfg.launcher === false
+		? []
+		: [
+				{
+					external_id: "launcher",
+					title: "Lutris",
+					role: "launcher",
+					launch: { kind: "launcher_ui", value: "lutris" },
+					platform: "PC",
+				},
+			];
+
 export const plugin = defineLibraryPlugin({
 	// One string: plugin id, provider id, store claim, and the id of the built-in scanner this
 	// replaces. It matches the package name and the repo name too, so there is no mapping to
@@ -160,6 +204,8 @@ export const plugin = defineLibraryPlugin({
 			});
 		}),
 
+	launchers: launcherEntries,
+
 	// Re-scan when Lutris writes: installing a game touches the database, and downloading art
 	// touches the cover directories.
 	watchDirs: (cfg) => {