Initial CLAP plugin scaffold for ES-5 encoder

Implements the full encoding pipeline for Expert Sleepers ES-5 with
ESX-8GT (gate) and ESX-8CV (CV) expanders as a native CLAP plugin.

Encoder logic ported from Expert Sleepers' MIT-licensed Pure Data
externals (https://github.com/expertsleepersltd/externals).

- ES-5 encoder: packs 6 × 8-bit header values into stereo 24-bit audio
- ESX-8GT encoder: 8 boolean gates → 1 byte
- ESX-8CV encoder: 8 × 12-bit CV values via 64-phase state machine
- 54 automatable parameters (6 header types + 48 gate/CV values)
- State save/load for preset support
- Builds on Linux (tested), macOS, and Windows

.gitignore

@@ -0,0 +1,10 @@
+build/
+cmake-build-*/
+.cache/
+compile_commands.json
+*.clap
+*.so
+*.dylib
+*.dll
+.idea/
+.vscode/