test(launcher): satisfy Linux runtime-plugin preflight in playback tests

The test-lane overhaul newly runs launcher/main.test.ts in CI via
test:launcher:unit:src. Three playback tests spawn the real launcher,
which on Linux runs ensureLinuxRuntimePluginAvailable — a preflight that
spawns the app with --ensure-linux-runtime-plugin-assets and polls up to
30s for an install response. The fake apps just exited, so the launcher
hung and the tests timed out (they passed on macOS only because the
preflight is a no-op off Linux).

Teach the fake apps to handle the preflight command: install the managed
plugin/theme under XDG_DATA_HOME and write the response file, mirroring
launcher/smoke.e2e.test.ts. Pin XDG_DATA_HOME under the temp home so the
app and preflight agree on the managed asset paths deterministically.

launcher/main.test.ts

@@ -65,11 +65,36 @@ function makeTestEnv(homeDir: string, xdgConfigHome: string): NodeJS.ProcessEnv
     APPDATA: xdgConfigHome,
     LOCALAPPDATA: path.join(homeDir, 'AppData', 'Local'),
     XDG_CONFIG_HOME: xdgConfigHome,
+    // Pin the data dir under the temp home so the Linux runtime-plugin preflight
+    // resolves managed asset paths deterministically (not the CI runner's).
+    XDG_DATA_HOME: path.join(homeDir, '.local', 'share'),
     PATH: pathValue,
     Path: pathValue,
   };
 }
 
+// On Linux the playback path runs `ensureLinuxRuntimePluginAvailable`, which —
+// when the runtime plugin/theme are missing — spawns the app with
+// `--ensure-linux-runtime-plugin-assets` and polls up to 30s
+// (RESPONSE_TIMEOUT_MS) for an install response. A fake app that just exits
+// never writes that response, so the launcher hangs and the test times out on
+// Linux CI (the preflight is a no-op on macOS/Windows). This shell prelude makes
+// the fake app install the managed plugin/theme and write the response, matching
+// launcher/smoke.e2e.test.ts. Prepend it to each fake app that reaches playback.
+const RUNTIME_PLUGIN_PREFLIGHT_SH = `if [ "$1" = "--ensure-linux-runtime-plugin-assets" ]; then
+  data="\${XDG_DATA_HOME:-$HOME/.local/share}/SubMiner"
+  mkdir -p "$data/plugin/subminer" "$data/themes"
+  printf -- '-- test plugin\\n' > "$data/plugin/subminer/main.lua"
+  printf 'test=true\\n' > "$data/plugin/subminer.conf"
+  printf '/* test theme */\\n' > "$data/themes/subminer.rasi"
+  if [ "$2" = "--ensure-linux-runtime-plugin-assets-response-path" ] && [ -n "$3" ]; then
+    mkdir -p "$(dirname "$3")"
+    printf '{"ok":true,"status":"installed","path":"%s"}' "$data/plugin/subminer/main.lua" > "$3"
+  fi
+  exit 0
+fi
+`;
+
 test('config path uses XDG_CONFIG_HOME override', () => {
   withTempDir((root) => {
     const xdgConfigHome = path.join(root, 'xdg');
@@ -237,7 +262,7 @@ test('doctor refresh-known-words forwards app refresh command without requiring
     const capturePath = path.join(root, 'captured-args.txt');
     fs.writeFileSync(
       appPath,
-      '#!/bin/sh\nif [ -n "$SUBMINER_TEST_CAPTURE" ]; then printf "%s\\n" "$@" > "$SUBMINER_TEST_CAPTURE"; fi\nexit 0\n',
+      `#!/bin/sh\n${RUNTIME_PLUGIN_PREFLIGHT_SH}if [ -n "$SUBMINER_TEST_CAPTURE" ]; then printf "%s\\n" "$@" > "$SUBMINER_TEST_CAPTURE"; fi\nexit 0\n`,
     );
     fs.chmodSync(appPath, 0o755);
 
@@ -264,7 +289,7 @@ test('launcher settings option forwards app settings window command', () => {
     const capturePath = path.join(root, 'captured-args.txt');
     fs.writeFileSync(
       appPath,
-      '#!/bin/sh\nif [ -n "$SUBMINER_TEST_CAPTURE" ]; then printf "%s\\n" "$@" > "$SUBMINER_TEST_CAPTURE"; fi\nexit 0\n',
+      `#!/bin/sh\n${RUNTIME_PLUGIN_PREFLIGHT_SH}if [ -n "$SUBMINER_TEST_CAPTURE" ]; then printf "%s\\n" "$@" > "$SUBMINER_TEST_CAPTURE"; fi\nexit 0\n`,
     );
     fs.chmodSync(appPath, 0o755);
 
@@ -288,7 +313,7 @@ test('launcher settings command forwards app settings window command', () => {
     const capturePath = path.join(root, 'captured-args.txt');
     fs.writeFileSync(
       appPath,
-      '#!/bin/sh\nif [ -n "$SUBMINER_TEST_CAPTURE" ]; then printf "%s\\n" "$@" > "$SUBMINER_TEST_CAPTURE"; fi\nexit 0\n',
+      `#!/bin/sh\n${RUNTIME_PLUGIN_PREFLIGHT_SH}if [ -n "$SUBMINER_TEST_CAPTURE" ]; then printf "%s\\n" "$@" > "$SUBMINER_TEST_CAPTURE"; fi\nexit 0\n`,
     );
     fs.chmodSync(appPath, 0o755);
 
@@ -369,7 +394,7 @@ test('launcher forwards --args to mpv as parsed tokens', { timeout: 15000 }, ()
         },
       }),
     );
-    fs.writeFileSync(appPath, '#!/bin/sh\nexit 0\n');
+    fs.writeFileSync(appPath, `#!/bin/sh\n${RUNTIME_PLUGIN_PREFLIGHT_SH}exit 0\n`);
     fs.chmodSync(appPath, 0o755);
 
     fs.writeFileSync(
@@ -460,7 +485,7 @@ test('launcher forwards non-info log level into mpv logging args', { timeout: 15
         },
       }),
     );
-    fs.writeFileSync(appPath, '#!/bin/sh\nexit 0\n');
+    fs.writeFileSync(appPath, `#!/bin/sh\n${RUNTIME_PLUGIN_PREFLIGHT_SH}exit 0\n`);
     fs.chmodSync(appPath, 0o755);
 
     fs.writeFileSync(
@@ -539,7 +564,7 @@ test('launcher routes youtube urls through regular playback startup', { timeout:
     );
     fs.writeFileSync(
       appPath,
-      '#!/bin/sh\nif [ -n "$SUBMINER_TEST_CAPTURE" ]; then printf "%s\\n" "$@" > "$SUBMINER_TEST_CAPTURE"; fi\nexit 0\n',
+      `#!/bin/sh\n${RUNTIME_PLUGIN_PREFLIGHT_SH}if [ -n "$SUBMINER_TEST_CAPTURE" ]; then printf "%s\\n" "$@" > "$SUBMINER_TEST_CAPTURE"; fi\nexit 0\n`,
     );
     fs.chmodSync(appPath, 0o755);
 
@@ -597,7 +622,7 @@ test('dictionary command forwards --dictionary and --dictionary-target to app co
     const capturePath = path.join(root, 'captured-args.txt');
     fs.writeFileSync(
       appPath,
-      '#!/bin/sh\nif [ -n "$SUBMINER_TEST_CAPTURE" ]; then printf "%s\\n" "$@" > "$SUBMINER_TEST_CAPTURE"; fi\nexit 0\n',
+      `#!/bin/sh\n${RUNTIME_PLUGIN_PREFLIGHT_SH}if [ -n "$SUBMINER_TEST_CAPTURE" ]; then printf "%s\\n" "$@" > "$SUBMINER_TEST_CAPTURE"; fi\nexit 0\n`,
     );
     fs.chmodSync(appPath, 0o755);
 
@@ -626,7 +651,7 @@ test('dictionary command forwards manual AniList selection modes to app command
     const capturePath = path.join(root, 'captured-args.txt');
     fs.writeFileSync(
       appPath,
-      '#!/bin/sh\nif [ -n "$SUBMINER_TEST_CAPTURE" ]; then printf "%s\\n" "$@" > "$SUBMINER_TEST_CAPTURE"; fi\nexit 0\n',
+      `#!/bin/sh\n${RUNTIME_PLUGIN_PREFLIGHT_SH}if [ -n "$SUBMINER_TEST_CAPTURE" ]; then printf "%s\\n" "$@" > "$SUBMINER_TEST_CAPTURE"; fi\nexit 0\n`,
     );
     fs.chmodSync(appPath, 0o755);
 
@@ -763,7 +788,7 @@ test('jellyfin discovery routes to app --background and remote announce with log
     const capturePath = path.join(root, 'captured-args.txt');
     fs.writeFileSync(
       appPath,
-      '#!/bin/sh\nif [ -n "$SUBMINER_TEST_CAPTURE" ]; then printf "%s\\n" "$@" > "$SUBMINER_TEST_CAPTURE"; fi\nexit 0\n',
+      `#!/bin/sh\n${RUNTIME_PLUGIN_PREFLIGHT_SH}if [ -n "$SUBMINER_TEST_CAPTURE" ]; then printf "%s\\n" "$@" > "$SUBMINER_TEST_CAPTURE"; fi\nexit 0\n`,
     );
     fs.chmodSync(appPath, 0o755);
 
@@ -790,7 +815,7 @@ test('jellyfin discovery via jf alias forwards remote announce for cast visibili
     const capturePath = path.join(root, 'captured-args.txt');
     fs.writeFileSync(
       appPath,
-      '#!/bin/sh\nif [ -n "$SUBMINER_TEST_CAPTURE" ]; then printf "%s\\n" "$@" > "$SUBMINER_TEST_CAPTURE"; fi\nexit 0\n',
+      `#!/bin/sh\n${RUNTIME_PLUGIN_PREFLIGHT_SH}if [ -n "$SUBMINER_TEST_CAPTURE" ]; then printf "%s\\n" "$@" > "$SUBMINER_TEST_CAPTURE"; fi\nexit 0\n`,
     );
     fs.chmodSync(appPath, 0o755);
 
@@ -817,7 +842,7 @@ test('jellyfin login routes credentials to app command', () => {
     const capturePath = path.join(root, 'captured-args.txt');
     fs.writeFileSync(
       appPath,
-      '#!/bin/sh\nif [ -n "$SUBMINER_TEST_CAPTURE" ]; then printf "%s\\n" "$@" > "$SUBMINER_TEST_CAPTURE"; fi\nexit 0\n',
+      `#!/bin/sh\n${RUNTIME_PLUGIN_PREFLIGHT_SH}if [ -n "$SUBMINER_TEST_CAPTURE" ]; then printf "%s\\n" "$@" > "$SUBMINER_TEST_CAPTURE"; fi\nexit 0\n`,
     );
     fs.chmodSync(appPath, 0o755);
 
@@ -856,7 +881,7 @@ test('jellyfin setup forwards password-store to app command', () => {
     const capturePath = path.join(root, 'captured-args.txt');
     fs.writeFileSync(
       appPath,
-      '#!/bin/sh\nif [ -n "$SUBMINER_TEST_CAPTURE" ]; then printf "%s\\n" "$@" > "$SUBMINER_TEST_CAPTURE"; fi\nexit 0\n',
+      `#!/bin/sh\n${RUNTIME_PLUGIN_PREFLIGHT_SH}if [ -n "$SUBMINER_TEST_CAPTURE" ]; then printf "%s\\n" "$@" > "$SUBMINER_TEST_CAPTURE"; fi\nexit 0\n`,
     );
     fs.chmodSync(appPath, 0o755);