chore(release): self-hosted updater on update.netralax.cloud

Switches the Tauri updater endpoint from GitHub Releases to a static
host. New Ed25519 pubkey (old private key was lost); existing 0.10.x
installs need one manual reinstall to pick up the new updater identity.

Release flow is now pnpm release <version> <notes> which bumps,
builds + signs locally, scps artifacts to the server, commits, tags.
GitHub workflow stays as workflow_dispatch backup (Windows only).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

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

@@ -42,8 +42,8 @@
   },
   "plugins": {
     "updater": {
-      "endpoints": ["https://github.com/byGalax/chat-app/releases/latest/download/latest.json"],
-      "pubkey": "dW50cnVzdGVkIGNvbW1lbnQ6IG1pbmlzaWduIHB1YmxpYyBrZXk6IDQ5N0U0RDcxOTU2OEQ0QUUKUldTdTFHaVZjVTErU1ZuMk1lWXBUbEcyS1RHYzJQN3k4VDdiUGRvRnVJYVJKR3BxWG1xcENpdlYK",
+      "endpoints": ["https://update.netralax.cloud/windows/latest.json"],
+      "pubkey": "dW50cnVzdGVkIGNvbW1lbnQ6IG1pbmlzaWduIHB1YmxpYyBrZXk6IEI1Mzc0QjVBQUZEQTA3RUIKUldUckI5cXZXa3MzdGM3QkE4WWFPd3NnVzRZeXdpcUM0eUtjRDlGN09ySEdzNXhLNlo3azBPajYK",
       "windows": {
         "installMode": "passive"
       }