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>

crates/audio/Cargo.toml

@@ -0,0 +1,8 @@
+[package]
+name = "kon-audio"
+version = "0.1.0"
+edition = "2021"
+description = "Audio capture (cpal), VAD, resampling (rubato), file decoding (symphonia), WAV I/O (hound) for Kon"
+
+[dependencies]
+kon-core = { path = "../core" }