feat(kon): scaffold hybrid modular workspace

- Cargo workspace with 6 domain crates: core, audio, transcription, ai-formatting, storage, cloud-providers
- Minimal Tauri shell (lib.rs + main.rs) with plugin registration
- Svelte 5 frontend copied from Ramble v0.2
- All crates compile as empty stubs
- App identifier: uk.co.corbel.kon

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/lib/components/Card.svelte

@@ -0,0 +1,7 @@
+<script>
+  let { children, classes = "" } = $props();
+</script>
+
+<div class="bg-bg-card border border-border rounded-2xl shadow-[0_1px_3px_rgba(0,0,0,0.2)] {classes}">
+  {@render children()}
+</div>