chore: scaffold minimal NIH-plug template

Based on musiikki/codename-206 patterns. Provides a clean, minimal
skeleton for new nih-plug audio plugins:

- Cargo.toml with pinned NIH-plug deps (same rev as codename-206)
- src/lib.rs — skeleton plugin with Params, Plugin impl, CLAP/VST3
- xtask/ — bundler xtask (cargo xtask bundle)
- bundler.toml — placeholder for bundle name
- .cargo/config.toml — xtask alias
- .gitignore — /target, /nih-plug, /_template
- LICENSE — Apache-2.0
- README.md — build and deploy instructions

src/lib.rs

@@ -0,0 +1,136 @@
+// SPDX-License-Identifier: Apache-2.0
+
+use nih_plug::prelude::*;
+use std::sync::Arc;
+
+// ──────────────────────────────────────────────
+// Params — add your plugin parameters here.
+// See musiikki/codename-206/src/params.rs for a real example.
+// ──────────────────────────────────────────────
+
+struct PluginParams;
+
+impl Params for PluginParams {
+    fn as_slice(&self) -> &[AtomicParam] {
+        &[]
+    }
+
+    fn as_mut_slice(&mut self) -> &mut [AtomicParam] {
+        &mut []
+    }
+
+    fn param_by_id(&self, _id: ParamId) -> Option<&AtomicParam> {
+        None
+    }
+
+    fn param_by_id_mut(&mut self, _id: ParamId) -> Option<&mut AtomicParam> {
+        None
+    }
+
+    fn param_by_name(&self, _name: &str) -> Option<&AtomicParam> {
+        None
+    }
+
+    fn param_by_name_mut(&mut self, _name: &str) -> Option<&mut AtomicParam> {
+        None
+    }
+}
+
+// ──────────────────────────────────────────────
+// Plugin
+// ──────────────────────────────────────────────
+
+struct MyPlugin {
+    params: Arc<PluginParams>,
+}
+
+impl Default for MyPlugin {
+    fn default() -> Self {
+        Self {
+            params: Arc::new(PluginParams),
+        }
+    }
+}
+
+impl Plugin for MyPlugin {
+    // TODO: Replace these placeholder values with your plugin's metadata.
+    const NAME: &'static str = "Plugin Name";
+    const VENDOR: &'static str = "Your Name";
+    const URL: &'static str = env!("CARGO_PKG_HOMEPAGE");
+    const EMAIL: &'static str = "your@email.com";
+
+    const VERSION: &'static str = env!("CARGO_PKG_VERSION");
+
+    const AUDIO_IO_LAYOUTS: &'static [AudioIOLayout] = &[
+        AudioIOLayout {
+            main_input_channels: NonZeroU32::new(2),
+            main_output_channels: NonZeroU32::new(2),
+            ..AudioIOLayout::const_default()
+        },
+    ];
+
+    const MIDI_INPUT: MidiConfig = MidiConfig::None;
+    const MIDI_OUTPUT: MidiConfig = MidiConfig::None;
+
+    const SAMPLE_ACCURATE_AUTOMATION: bool = true;
+
+    type SysSysexMessage = ();
+    type BackgroundTask = ();
+
+    fn params(&self) -> Arc<dyn Params> {
+        self.params.clone()
+    }
+
+    fn editor(&mut self, _async_executor: AsyncExecutor<Self>) -> Option<Box<dyn Editor>> {
+        // TODO: Implement your egui editor here.
+        // return Some(Box::new(MyEditor::new(self.params.clone())));
+        None
+    }
+
+    fn initialize(
+        &mut self,
+        _audio_io_layout: &AudioIOLayout,
+        _buffer_config: &BufferConfig,
+        _context: &mut impl InitContext<Self>,
+    ) -> bool {
+        true
+    }
+
+    fn reset(&mut self) {}
+
+    fn process(
+        &mut self,
+        buffer: &mut Buffer,
+        _aux: &mut AuxiliaryBuffers,
+        _context: &mut impl ProcessContext<Self>,
+    ) -> ProcessStatus {
+        // TODO: Implement your DSP here.
+        // This is a passthrough — replace with your audio processing.
+        for mut frame in buffer.iter_samples() {
+            for ch in 0..frame.len() {
+                *frame.get_mut(ch).unwrap() = *frame.get(ch).unwrap();
+            }
+        }
+        ProcessStatus::Normal
+    }
+}
+
+impl ClapPlugin for MyPlugin {
+    // TODO: Replace with a unique CLAP ID, e.g. "com.your-domain.your-plugin-name"
+    const CLAP_ID: &'static str = "com.your-domain.plugin-name";
+    const CLAP_DESCRIPTION: Option<&'static str> = Some("Your plugin description");
+    const CLAP_MANUAL_URL: Option<&'static str> = Some(Self::URL);
+    const CLAP_SUPPORT_URL: Option<&'static str> = None;
+    const CLAP_FEATURES: &'static [ClapFeature] = &[ClapFeature::AudioEffect];
+}
+
+impl Vst3Plugin for MyPlugin {
+    // TODO: Replace with a unique 16-byte Class ID.
+    // Must be exactly 16 bytes — padded with '!' if shorter.
+    const VST3_CLASS_ID: [u8; 16] = *b"Unique16CharId!!";
+    const VST3_SUBCATEGORIES: &'static [Vst3SubCategory] =
+        &[Vst3SubCategory::Fx];
+}
+
+nih_export_clap!(MyPlugin);
+nih_export_vst3!(MyPlugin);