Added Oxibadge, a minimal Tauri + Svelte desktop client

Scaffolds the oxibadge crate/frontend as a new workspace member, stripped
down to a bare hello-world, and
extends the CI pipeline

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

oxibadge/src-tauri/.gitignore

@@ -0,0 +1,7 @@
+# Generated by Cargo
+# will have compiled files and executables
+/target/
+
+# Generated by Tauri
+# will have schema files for capabilities auto-completion
+/gen/schemas