Add Tauri launcher with Svelte UI

- Accounts: panel login/sign-up, Microsoft device-code sign-in, offline
  play; tokens encrypted with a key kept in the OS credential store
- Home: instance rail, live server status, news feed, social links,
  Play button with download progress, speed and ETA
- Full settings: accounts, memory/resolution/after-launch behaviour,
  Java and GC presets, Minecraft keybind editor applied to options.txt,
  theme overrides, storage manager, self-update via GitHub releases
- Game console, crash dialog with hints, per-instance overrides
- Live admin branding (colours, fonts, backgrounds, custom CSS)
- Online install tests for vanilla/Fabric/Quilt/Forge/NeoForge (CI)

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_011ARcGWxLx21FwXJ3yfGriS

crates/core/src/launch.rs

@@ -268,7 +268,10 @@ fn write_argfile(path: &Path, args: &[String]) -> Result<()> {
     Ok(())
 }
 
-pub fn spawn(cmd: &Command, java_major: u32) -> Result<tokio::process::Child> {
+/// Start the game. With `capture` the game's stdout/stderr are piped back to
+/// us (for the console); without it they're discarded, which is required
+/// when the launcher exits while the game keeps running.
+pub fn spawn(cmd: &Command, java_major: u32, capture: bool) -> Result<tokio::process::Child> {
     std::fs::create_dir_all(&cmd.cwd)?;
     let mut proc = tokio::process::Command::new(&cmd.java);
     let total_len: usize = cmd.args.iter().map(|a| a.len() + 3).sum();
@@ -280,10 +283,8 @@ pub fn spawn(cmd: &Command, java_major: u32) -> Result<tokio::process::Child> {
     } else {
         proc.args(&cmd.args);
     }
-    proc.current_dir(&cmd.cwd)
-        .stdin(std::process::Stdio::null())
-        .stdout(std::process::Stdio::piped())
-        .stderr(std::process::Stdio::piped());
+    let out = || if capture { std::process::Stdio::piped() } else { std::process::Stdio::null() };
+    proc.current_dir(&cmd.cwd).stdin(std::process::Stdio::null()).stdout(out()).stderr(out());
     #[cfg(windows)]
     proc.creation_flags(0x0800_0000);
     proc.spawn().with_context(|| format!("starting {}", cmd.java.display()))

crates/core/tests/online.rs

@@ -0,0 +1,81 @@
+//! Real-network installs against Mojang / Fabric / Forge / NeoForge.
+//! Ignored by default; CI runs them with `cargo test -p scopenet-core --test online -- --ignored`.
+
+use scopenet_core::install::{install, InstallSpec};
+use scopenet_core::launch::{self, Auth, GcPreset, LaunchOptions};
+use scopenet_core::{progress, Layout};
+use scopenet_shared::Loader;
+
+async fn run(mc: &str, loader: Loader) {
+    let root = std::env::var("SCOPENET_TEST_ROOT").map(std::path::PathBuf::from).unwrap_or_else(|_| std::env::temp_dir().join("scopenet-online"));
+    let layout = Layout::new(&root);
+    let client = scopenet_core::http::client();
+    let game_dir = layout.instance_dir(&format!("{mc}-{}", loader.as_str()));
+    let spec = InstallSpec { mc_version: mc.into(), loader, loader_version: None, java_override: None, game_dir: game_dir.clone(), concurrency: 16, deep_verify: false };
+    let installed = install(&client, &layout, &spec, &progress::noop()).await.unwrap_or_else(|e| panic!("{mc} {loader:?}: {e:#}"));
+
+    for path in installed.classpath(&layout) {
+        assert!(path.exists(), "missing classpath entry {}", path.display());
+    }
+    assert!(installed.java.exists(), "java missing at {}", installed.java.display());
+
+    let opts = LaunchOptions {
+        auth: Auth { username: "CiBot".into(), uuid: scopenet_shared::offline_uuid("CiBot"), access_token: "0".into(), user_type: "legacy".into(), xuid: None },
+        game_dir,
+        memory_min_mb: 512,
+        memory_max_mb: 2048,
+        gc: GcPreset::G1,
+        extra_jvm_args: vec![],
+        resolution: None,
+        fullscreen: false,
+        join_server: Some(("example.org".into(), 25565)),
+        version_label: "ci".into(),
+        launcher_name: "scopenet".into(),
+        launcher_version: "ci".into(),
+    };
+    let cmd = launch::build(&installed, &layout, &opts);
+    let joined = cmd.args.join(" ");
+    assert!(!joined.contains("${"), "unsubstituted placeholder in: {joined}");
+
+    // The downloaded runtime must actually run.
+    let out = std::process::Command::new(scopenet_core::java::sibling_exe(&installed.java, false)).arg("-version").output().unwrap();
+    assert!(out.status.success());
+    println!("{mc} {loader:?}: OK ({} classpath entries, java {})", installed.classpath(&layout).len(), installed.java_major);
+}
+
+#[tokio::test]
+#[ignore]
+async fn vanilla_latest_release() {
+    let m = scopenet_core::meta::mojang_manifest(&scopenet_core::http::client()).await.unwrap();
+    run(&m.latest.release, Loader::Vanilla).await;
+}
+
+#[tokio::test]
+#[ignore]
+async fn vanilla_legacy_1_8_9() {
+    run("1.8.9", Loader::Vanilla).await;
+}
+
+#[tokio::test]
+#[ignore]
+async fn fabric_1_21_1() {
+    run("1.21.1", Loader::Fabric).await;
+}
+
+#[tokio::test]
+#[ignore]
+async fn quilt_1_20_1() {
+    run("1.20.1", Loader::Quilt).await;
+}
+
+#[tokio::test]
+#[ignore]
+async fn forge_1_20_1() {
+    run("1.20.1", Loader::Forge).await;
+}
+
+#[tokio::test]
+#[ignore]
+async fn neoforge_1_21_1() {
+    run("1.21.1", Loader::NeoForge).await;
+}