fix(desktop): restore managed Node server startup (#348)

## Summary
- revert the Bun standalone desktop packaging path and restore the
server's original `dist/bin.js` bootstrap flow
- add a managed Node runtime for Electron and Tauri that downloads only
the current platform/arch artifact into `~/.config/codenomad`
- update desktop startup and packaging scripts so packaged apps use the
managed runtime consistently, and clean up Electron's expected
navigation-abort log noise

## Testing
- npm run typecheck --workspace @neuralnomads/codenomad-electron-app
- cargo check
- npm run build --workspace @neuralnomads/codenomad
- npm run build:mac --workspace @neuralnomads/codenomad-electron-app
- launch
`packages/electron-app/release/mac-arm64/CodeNomad.app/Contents/MacOS/CodeNomad`
and verify the packaged server reaches ready with the managed Node
runtime

packages/electron-app/scripts/build.js

@@ -1,7 +1,7 @@
 #!/usr/bin/env node
 
 import { spawn } from "child_process"
-import { existsSync, readFileSync } from "fs"
+import { existsSync } from "fs"
 import path, { join } from "path"
 import { fileURLToPath } from "url"
 
@@ -14,46 +14,6 @@ const npxCmd = process.platform === "win32" ? "npx.cmd" : "npx"
 const nodeModulesPath = join(appDir, "node_modules")
 const workspaceNodeModulesPath = join(workspaceRoot, "node_modules")
 
-function getPlatformEsbuildPackage() {
-  const platformKey = `${process.platform}-${process.arch}`
-  const platformPackages = {
-    "linux-x64": "@esbuild/linux-x64",
-    "linux-arm64": "@esbuild/linux-arm64",
-    "darwin-arm64": "@esbuild/darwin-arm64",
-    "darwin-x64": "@esbuild/darwin-x64",
-    "win32-arm64": "@esbuild/win32-arm64",
-    "win32-x64": "@esbuild/win32-x64",
-  }
-
-  return platformPackages[platformKey] ?? null
-}
-
-async function ensureEsbuildPlatformBinary() {
-  const pkgName = getPlatformEsbuildPackage()
-  if (!pkgName) {
-    return
-  }
-
-  const platformPackagePath = join(workspaceNodeModulesPath, ...pkgName.split("/"))
-  if (existsSync(platformPackagePath)) {
-    return
-  }
-
-  let esbuildVersion = ""
-  try {
-    esbuildVersion = JSON.parse(readFileSync(join(workspaceNodeModulesPath, "esbuild", "package.json"), "utf-8")).version ?? ""
-  } catch {
-    // leave version empty; fallback install will use latest compatible
-  }
-
-  const packageSpec = esbuildVersion ? `${pkgName}@${esbuildVersion}` : pkgName
-  console.log("📦 Step 0/3: Restoring esbuild platform binary...\n")
-  await run(npmCmd, ["install", packageSpec, "--no-save", "--ignore-scripts", "--fund=false", "--audit=false"], {
-    cwd: workspaceRoot,
-    env: { NODE_PATH: workspaceNodeModulesPath },
-  })
-}
-
 const platforms = {
   mac: {
     args: ["--mac", "--x64", "--arm64"],
@@ -145,8 +105,6 @@ async function build(platform) {
   console.log(`\n🔨 Building for: ${config.description}\n`)
 
   try {
-    await ensureEsbuildPlatformBinary()
-
     console.log("📦 Step 1/3: Building CLI dependency...\n")
     await run(npmCmd, ["run", "build", "--workspace", "@neuralnomads/codenomad"], {
       cwd: workspaceRoot,