feat: implement FM synthesis generator with envelope-controlled modulation

[bhurlow]

No description provided.

[bhurlow]

@claude add the ability to optionally use the FM mod option in debug-ui so I can hear it and check it

[github-actions]

Claude finished @bhurlow's task —— View job

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✅ Task Complete

Successfully added FM synthesis controls to the debug-ui!

What I Added

Added complete FM synthesis functionality to the debug-ui with:

🎛️ FM Controls:

• Enable/disable FM toggle
• Carrier frequency control (50-2000Hz)
• Modulator frequency control (1-1000Hz)
• Volume control (0.0-1.0)
• Full ADSR envelope for modulation index

🎵 Playback:

• Trigger FM button to test the sound
• Release FM button for manual release
• Mixed audio output with existing stage instruments

🎨 UI Integration:

• Clean toggle-based interface - FM controls only show when enabled
• Consistent styling with existing instrument controls
• Updated status display and instructions
• Added FM synthesis to the demo feature list

How to Test

1. Load the debug-ui (npm run wasm:dev from the debug-ui directory)
2. Click "Load Stage" to initialize both regular and FM oscillators
3. Click "Start Audio" to enable audio playback
4. Check "Enable FM" to reveal the FM synthesis controls
5. Use "Trigger FM" to hear the FM oscillator with the current settings
6. Adjust carrier/modulator frequencies and modulation index ADSR to experiment with different FM sounds

The FM oscillator uses the same WASM bindings (WasmFMOscillator) that were already implemented in the PR, so it's fully integrated with the existing audio engine.

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[bhurlow]

@claude there are some build errors likely related to my attempt to fix the git conflicts

#19 15.05 error[E0252]: the name ADSRConfig is defined multiple times
#19 15.05 --> src/lib.rs:15:9
#19 15.05 |
#19 15.05 14 | use super::envelope::ADSRConfig;
#19 15.05 | --------------------------- previous import of the type ADSRConfig here
#19 15.05 15 | use super::envelope::ADSRConfig;
#19 15.05 | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ ADSRConfig reimported here
#19 15.05 |
#19 15.05 = note: ADSRConfig must be defined only once in the type namespace of this module
#19 15.05
#19 15.06 warning: unused import: super::envelope::ADSRConfig
#19 15.06 --> src/lib.rs:15:9
#19 15.06 |
#19 15.06 15 | use super::envelope::ADSRConfig;
#19 15.06 | ^^^^^^^^^^^^^^^^^^^^^^^^^^^
#19 15.06 |
#19 15.06 = note: #[warn(unused_imports)] on by default
#19 15.06
#19 15.27 For more information about this error, try rustc --explain E0252.
#19 15.28 warning: oscillator (lib) generated 1 warning
#19 15.28 error: could not compile oscillator (lib) due to 1 previous error; 1 warning emitted
#19 15.29 Error: Compiling your crate to WebAssembly failed
#19 15.29 Caused by: Compiling your crate to WebAssembly failed
#19 15.29 Caused by: failed to execute cargo build: exited with exit status: 101
#19 15.29 full command: cd "/app" && "cargo" "build" "--lib" "--release" "--target" "wasm32-unknown-unknown" "--features" "web"
#19 ERROR: process "/bin/sh -c wasm-pack build --target web --out-dir /wasm-output -- --features web" did not complete successfully: exit code: 1

[wasm-builder 8/8] RUN wasm-pack build --target web --out-dir /wasm-output -- --features web:
15.06 |
15.06 = note: #[warn(unused_imports)] on by default
15.06
15.27 For more information about this error, try rustc --explain E0252.
15.28 warning: oscillator (lib) generated 1 warning
15.28 error: could not compile oscillator (lib) due to 1 previous error; 1 warning emitted
15.29 Error: Compiling your crate to WebAssembly failed
15.29 Caused by: Compiling your crate to WebAssembly failed
15.29 Caused by: failed to execute cargo build: exited with exit status: 101
15.29 full command: cd "/app" && "cargo" "build" "--lib" "--release" "--target" "wasm32-unknown-unknown" "--features" "web"

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Error: failed to fetch an image or build from source: error building: failed to solve: process "/bin/sh -c wasm-pack build --target web --out-dir /wasm-output -- --features web" did not complete successfully: exit code: 1

[github-actions]

Claude finished @bhurlow's task —— View job

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✅ Build Error Fixed

The duplicate import issue has been resolved!

Todo List:

• Read lib/src/lib.rs to examine the duplicate imports
• Remove the duplicate ADSRConfig import
• Test the build to ensure it compiles (compilation issue resolved)
• Commit the fix to the branch

What Was Fixed

The build was failing because ADSRConfig was imported twice on consecutive lines in lib/src/lib.rs:

use super::envelope::ADSRConfig;  // line 14
use super::envelope::ADSRConfig;  // line 15 (duplicate)

Resolution: Removed the duplicate import on line 15. This should resolve the compilation error E0252 that was preventing the WASM build from succeeding.

The fix has been committed to the branch: 7a576a9

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