feat(06-01): scaffold apps/desktop as @tessera/desktop Tauri 2.x project

- Create Tauri project structure with Cargo.toml, tauri.conf.json, build.rs
- Implement lib.rs with store plugin and server URL navigation on startup
- Configure capabilities with core:default and store:default permissions
- Set frontendDist to ../src for local setup page (no bundled frontend)
- Add placeholder icons for build compatibility (to be replaced in 06-02)
- Add Cargo target/ to .gitignore
- Window config: 1280x800, centered, native decorations, resizable

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

apps/desktop/src-tauri/Cargo.toml

@@ -0,0 +1,17 @@
+[package]
+name = "tessera-desktop"
+version = "0.0.1"
+edition = "2021"
+
+[lib]
+name = "tessera_desktop_lib"
+crate-type = ["cdylib", "staticlib", "rlib"]
+
+[build-dependencies]
+tauri-build = { version = "2", features = [] }
+
+[dependencies]
+tauri = { version = "2", features = ["tray-icon"] }
+tauri-plugin-store = "2"
+serde = { version = "1", features = ["derive"] }
+serde_json = "1"

apps/desktop/src-tauri/build.rs

@@ -0,0 +1,3 @@
+fn main() {
+    tauri_build::build()
+}

apps/desktop/src-tauri/capabilities/default.json

@@ -0,0 +1,10 @@
+{
+  "$schema": "../gen/schemas/desktop-schema.json",
+  "identifier": "default",
+  "description": "Tessera desktop capabilities",
+  "windows": ["main"],
+  "permissions": [
+    "core:default",
+    "store:default"
+  ]
+}

apps/desktop/src-tauri/src/lib.rs

@@ -0,0 +1,36 @@
+use tauri::Manager;
+use tauri_plugin_store::StoreExt;
+
+/// Main entry point for the Tessera desktop application.
+///
+/// Registers plugins, checks for a stored server URL on startup,
+/// and either navigates to the configured server or shows the
+/// bundled setup page for first-run configuration.
+pub fn run() {
+    tauri::Builder::default()
+        .plugin(tauri_plugin_store::Builder::new().build())
+        .setup(|app| {
+            // Attempt to read a previously stored server URL
+            let store = app.store("config.json")?;
+            let server_url = store.get("server_url");
+
+            if let Some(url_value) = server_url {
+                if let Some(url_str) = url_value.as_str() {
+                    if !url_str.is_empty() {
+                        // Navigate the main window to the configured server URL
+                        if let Some(window) = app.get_webview_window("main") {
+                            if let Ok(parsed) = url_str.parse::<tauri::Url>() {
+                                let _ = window.navigate(parsed);
+                            }
+                        }
+                    }
+                }
+            }
+            // If no server_url is stored, the WebView remains on the
+            // bundled setup page (frontendDist = ../src/setup.html)
+
+            Ok(())
+        })
+        .run(tauri::generate_context!())
+        .expect("error while running Tessera desktop application");
+}

apps/desktop/src-tauri/src/main.rs

@@ -0,0 +1,6 @@
+// Prevents additional console window on Windows in release, DO NOT REMOVE!!
+#![cfg_attr(not(debug_assertions), windows_subsystem = "windows")]
+
+fn main() {
+    tessera_desktop_lib::run()
+}

apps/desktop/src-tauri/tauri.conf.json

@@ -0,0 +1,32 @@
+{
+  "$schema": "https://raw.githubusercontent.com/tauri-apps/tauri/dev/crates/tauri-config-schema/schema.json",
+  "productName": "Tessera",
+  "version": "0.0.1",
+  "identifier": "de.ctl.tessera.desktop",
+  "build": {
+    "frontendDist": "../src",
+    "devUrl": "http://localhost:1420"
+  },
+  "app": {
+    "withGlobalTauri": true,
+    "windows": [
+      {
+        "label": "main",
+        "title": "Tessera",
+        "width": 1280,
+        "height": 800,
+        "center": true,
+        "decorations": true,
+        "resizable": true
+      }
+    ],
+    "security": {
+      "csp": "default-src 'self' 'unsafe-inline' 'unsafe-eval'; connect-src *; img-src * data:; font-src * data:; style-src 'self' 'unsafe-inline' *; script-src 'self' 'unsafe-inline' 'unsafe-eval' https://unpkg.com"
+    }
+  },
+  "bundle": {
+    "active": true,
+    "targets": ["appimage", "nsis"],
+    "icon": ["icons/icon.png", "icons/icon.ico"]
+  }
+}