Don't depend on Node anymore (#346)

## Summary
- package `packages/server` as a standalone desktop executable so
Electron and Tauri no longer depend on a system-installed Node runtime
in production
- align Electron and Tauri startup logic around launching the packaged
server, resolving binaries from the user shell, and bundling the same
server resources into both desktop apps
- replace the workspace instance proxy path that used
`@fastify/reply-from` with a direct streaming proxy so packaged
standalone builds can talk to spawned `opencode` instances correctly

## Why
Desktop production builds were still depending on a user-provided Node
runtime to launch `packages/server`, which made packaging less
self-contained and created different behavior across machines. While
moving to a standalone server executable, we also found that
Bun-compiled standalone builds could start `opencode` successfully but
failed when proxying requests to those instances through `reply-from`.

The goal of this change is to make desktop production startup
self-contained, keep Electron and Tauri behavior aligned, and restore
correct communication with local `opencode` instances in packaged
builds.

## What Changed
- added a standalone build path for `packages/server` and bundle
`codenomad-server` into desktop resources
- updated Electron production startup to resolve and launch the
standalone server executable
- updated Tauri production startup to resolve and launch the standalone
server executable with matching cwd and shell behavior
- added runtime path helpers so the packaged server can reliably find
its bundled UI, auth templates, config template, and package metadata
- improved bare binary resolution so commands like `opencode` can be
resolved from the user's login shell environment
- upgraded the server stack to newer Fastify-compatible packages needed
for the standalone/runtime work
- replaced the workspace instance proxy implementation with a direct
streaming proxy for requests to spawned `opencode` instances
- updated Electron and Tauri build/prebuild scripts to generate and
package the standalone server, while also repairing missing
platform-specific optional binaries during packaging

## Benefits
- desktop production builds no longer require Node to be installed on
the user's system
- Electron and Tauri now use the same packaged server model in
production, reducing platform drift
- packaged desktop apps can successfully create workspaces, launch
`opencode`, and proxy health/session traffic to those instances
- the server bundle is more self-contained and resilient to different
launch environments
- desktop packaging is more predictable because the required server
executable is built and bundled as part of the app build flow

packages/server/scripts/copy-opencode-config.mjs

@@ -1,6 +1,6 @@
 #!/usr/bin/env node
 import { spawnSync } from "child_process"
-import { cpSync, existsSync, mkdirSync, rmSync } from "fs"
+import { cpSync, existsSync, mkdirSync, readdirSync, rmSync } from "fs"
 import path from "path"
 import { fileURLToPath } from "url"
 
@@ -14,6 +14,67 @@ const selfLinkDir = path.resolve(nodeModulesDir, "@codenomad", "opencode-config"
 const npmExecPath = process.env.npm_execpath
 const npmNodeExecPath = process.env.npm_node_execpath
 
+function stripNodeModuleBins(rootDir) {
+  const root = path.join(rootDir, "node_modules")
+  if (!existsSync(root)) {
+    return 0
+  }
+
+  const stack = [root]
+  let removed = 0
+
+  while (stack.length > 0) {
+    const current = stack.pop()
+    if (!current) break
+
+    let entries
+    try {
+      entries = readdirSync(current, { withFileTypes: true })
+    } catch {
+      continue
+    }
+
+    for (const entry of entries) {
+      const full = path.join(current, entry.name)
+      if (entry.name === ".bin") {
+        rmSync(full, { recursive: true, force: true })
+        removed += 1
+        continue
+      }
+
+      if (entry.isDirectory()) {
+        stack.push(full)
+      }
+    }
+  }
+
+  return removed
+}
+
+function stripOptionalNativeAddons(rootDir) {
+  const nodeModulesRoot = path.join(rootDir, "node_modules")
+  if (!existsSync(nodeModulesRoot)) {
+    return 0
+  }
+
+  const removablePaths = [
+    path.join(nodeModulesRoot, "@msgpackr-extract"),
+    path.join(nodeModulesRoot, "msgpackr-extract"),
+  ]
+
+  let removed = 0
+  for (const targetPath of removablePaths) {
+    if (!existsSync(targetPath)) {
+      continue
+    }
+
+    rmSync(targetPath, { recursive: true, force: true })
+    removed += 1
+  }
+
+  return removed
+}
+
 if (!existsSync(sourceDir)) {
   console.error(`[copy-opencode-config] Missing source directory at ${sourceDir}`)
   process.exit(1)
@@ -58,4 +119,14 @@ rmSync(targetDir, { recursive: true, force: true })
 mkdirSync(path.dirname(targetDir), { recursive: true })
 cpSync(sourceDir, targetDir, { recursive: true })
 
+const removedBins = stripNodeModuleBins(targetDir)
+if (removedBins > 0) {
+  console.log(`[copy-opencode-config] Removed ${removedBins} node_modules/.bin directories`)
+}
+
+const removedNativeAddons = stripOptionalNativeAddons(targetDir)
+if (removedNativeAddons > 0) {
+  console.log(`[copy-opencode-config] Removed ${removedNativeAddons} optional native addon package paths`)
+}
+
 console.log(`[copy-opencode-config] Copied ${sourceDir} -> ${targetDir}`)