chore(release): bump client version to 1.1.0-alpha.3 (#1279)

The server takes its version from the tag via ldflags, but the client's is
pinned in package.json, tauri.conf.json and Cargo.toml. Without this bump the
v1.1.0-alpha.3 tag would build an installer still identifying as alpha.2, and
the client updater compares that string against the server's manifest — so a
stale value means clients never see the update.

Lockfiles follow (npm + cargo); README's build examples updated to match.

Co-authored-by: Claude Opus 5 (1M context) <noreply@anthropic.com>

Client/tauri-client/package.json

@@ -1,7 +1,7 @@
 {
   "name": "owncord-client",
   "private": true,
-  "version": "1.1.0-alpha.2",
+  "version": "1.1.0-alpha.3",
   "type": "module",
   "scripts": {
     "dev": "vite",