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>

static/pcm-processor.js

@@ -0,0 +1,43 @@
+class PcmProcessor extends AudioWorkletProcessor {
+  constructor() {
+    super();
+    this.buffer = [];
+    // sampleRate is a global in AudioWorkletProcessor scope
+    this.ratio = sampleRate / 16000;
+    this.needsResample = Math.abs(this.ratio - 1.0) > 0.01;
+    this.resamplePos = 0;
+  }
+
+  process(inputs) {
+    const input = inputs[0];
+    if (!input || input.length === 0) return true;
+
+    const samples = input[0]; // First channel (mono)
+    if (!samples) return true;
+
+    if (this.needsResample) {
+      // Simple downsampling to 16kHz
+      for (let i = 0; i < samples.length; i++) {
+        this.resamplePos += 1;
+        if (this.resamplePos >= this.ratio) {
+          this.buffer.push(samples[i]);
+          this.resamplePos -= this.ratio;
+        }
+      }
+    } else {
+      for (let i = 0; i < samples.length; i++) {
+        this.buffer.push(samples[i]);
+      }
+    }
+
+    // Send every ~0.5 seconds at 16kHz = 8000 samples
+    if (this.buffer.length >= 8000) {
+      this.port.postMessage({ type: "pcm", samples: this.buffer });
+      this.buffer = [];
+    }
+
+    return true;
+  }
+}
+
+registerProcessor("pcm-processor", PcmProcessor);