chore: bump crate and extension versions to 0.5.0

Catches the workspace and the extension manifests up to the v0.5.x
release line (was still showing 0.2.0).

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

extension/manifest.firefox.json

@@ -1,7 +1,7 @@
 {
   "manifest_version": 3,
   "name": "Relicario",
-  "version": "0.2.0",
+  "version": "0.5.0",
   "description": "Two-factor encrypted password manager",
   "icons": {
     "16": "icons/icon-16.png",