Add Go project scaffold for Wails v2 SSH/Telnet/RAW TCP client

- go.mod with Wails v2.9.2, x/crypto, go-sqlite3, go-keyring, uuid
- cmd/app/main.go: Wails entry point (Nexus Terminal, 1400x900, #1a1a2e)
- internal/app/app.go: lifecycle (Startup/Shutdown/DomReady)
- internal/models/models.go: full model definitions (Profile, SSHConfig,
  TelnetConfig, RAWConfig, SessionInfo, KnownHost, AppPreferences, etc.)
- internal/models/defaults.go: default values and NewProfile factory
- internal/validation/validation.go: thorough field-level validation
- frontend/embed.go: embedded frontend assets
- Updated existing storage, secrets, config to match new model structure

frontend/scripts/copy-assets.js

@@ -0,0 +1,83 @@
+/**
+ * copy-assets.js — Copies xterm library assets from node_modules into
+ * the frontend source tree so they can be served directly by Wails.
+ *
+ * Run automatically via the postinstall hook in package.json.
+ */
+'use strict';
+
+const fs   = require('fs');
+const path = require('path');
+
+const frontendDir = path.resolve(__dirname, '..');
+
+// Mapping: source (relative to node_modules) → destination (relative to frontend/)
+const assets = [
+  {
+    src:  'xterm/css/xterm.css',
+    dest: 'src/css/lib/xterm.css',
+  },
+  {
+    src:  'xterm/lib/xterm.js',
+    dest: 'src/js/lib/xterm.min.js',
+  },
+  {
+    src:  'xterm-addon-fit/lib/xterm-addon-fit.js',
+    dest: 'src/js/lib/xterm-addon-fit.min.js',
+  },
+  {
+    src:  'xterm-addon-search/lib/xterm-addon-search.js',
+    dest: 'src/js/lib/xterm-addon-search.min.js',
+  },
+  {
+    src:  'xterm-addon-web-links/lib/xterm-addon-web-links.js',
+    dest: 'src/js/lib/xterm-addon-web-links.min.js',
+  },
+];
+
+/**
+ * Ensures the parent directory of the given file path exists.
+ */
+function ensureDir(filePath) {
+  const dir = path.dirname(filePath);
+  if (!fs.existsSync(dir)) {
+    fs.mkdirSync(dir, { recursive: true });
+  }
+}
+
+/**
+ * Copies a single asset, logging the result.
+ */
+function copyAsset(entry) {
+  const srcPath  = path.join(frontendDir, 'node_modules', entry.src);
+  const destPath = path.join(frontendDir, entry.dest);
+
+  if (!fs.existsSync(srcPath)) {
+    console.error(`  ✗ Source not found: ${entry.src}`);
+    return false;
+  }
+
+  ensureDir(destPath);
+  fs.copyFileSync(srcPath, destPath);
+  console.log(`  ✓ ${entry.src} → ${entry.dest}`);
+  return true;
+}
+
+// --- Main ---
+
+console.log('[copy-assets] Copying xterm library files…');
+
+let failures = 0;
+for (const entry of assets) {
+  if (!copyAsset(entry)) {
+    failures++;
+  }
+}
+
+if (failures > 0) {
+  console.error(`\n[copy-assets] ${failures} file(s) could not be copied.`);
+  console.error('[copy-assets] Have you run "npm install" first?');
+  process.exit(1);
+}
+
+console.log('[copy-assets] All assets copied successfully.');