Initial release: 8-bit sound synthesizer with LLM/MCP integration

Soundgen is a Rust workspace for generating 8-bit/chiptune sound effects,
UI sounds, and ambient textures for game audio assets. It features JSON-first
sound specs, an MCP server for LLM tool-use, an egui GUI editor, and a
runtime library with NES-authentic DAC emulation.

Features:
- 6 voice types: pulse, triangle, noise, DPCM, wavetable, FM
- Effects: ADSR envelope, frequency sweep, biquad filter, vibrato
- 13 built-in presets (SFX/UI/ambient) as JSON data files
- MCP server: list_presets, generate_sfx, render_sound tools
- Pattern-based sequencer (JSON song format)
- egui GUI: virtual keyboard, preset browser, channel editor, undo/redo
- Runtime: NES nonlinear DAC + SoundBank for game embedding
- 90 tests, 0 warnings

Crates:
- soundgen-core: synthesis engine (no I/O)
- soundgen-fmt: SoundSpec JSON schema + PresetRegistry
- soundgen-io: WAV writer + audio playback
- soundgen-seq: sequencer (patterns, songs)
- soundgen-cli: gen/render/render-song/list-presets
- soundgen-mcp: MCP server for LLM integration
- soundgen-gui: egui editor
- soundgen-runtime: NES DAC + SoundBank

.github/workflows/ci.yml

@@ -0,0 +1,41 @@
+name: CI
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+    branches: [main]
+
+env:
+  CARGO_TERM_COLOR: always
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Install ALSA dev
+        run: sudo apt-get update && sudo apt-get install -y libasound2-dev
+
+      - uses: dtolnay/rust-toolchain@stable
+
+      - name: Build
+        run: cargo build --workspace --verbose
+
+      - name: Build GUI
+        run: cargo build -p soundgen-gui --verbose
+
+      - name: Test
+        run: cargo test --workspace --verbose
+
+      - name: Build examples
+        run: cargo build --workspace --examples --verbose
+
+      - name: Clippy
+        run: cargo clippy --workspace -- -D warnings
+        continue-on-error: true
+
+      - name: Format check
+        run: cargo fmt --all -- --check
+        continue-on-error: true