feat: add resonance compressor and Windows CI

docs/resonance-compressor.md

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+# Resonance Compressor 0.1
+
+A mixing effect for controlling local spectral peaks while retaining the intended
+sound. Independently designed in Rust; no claim of matching Soothe or Quance.
+
+![Resonance Compressor](resonance-editor.png)
+
+## Install on Windows
+
+Download the Windows artifact from the GitLab pipeline's **windows** job and
+extract the ZIP. Copy `Resonance Compressor.clap` into
+`C:\Program Files\Common Files\CLAP\`. In FL Studio 2024.1 or newer, open
+Options → Manage plugins, enable Verify plugins, and Find installed plugins.
+Load Resonance Compressor in a mixer effect slot. Keep the font license with
+redistributed packages.
+
+## Work with it
+
+Loop a troublesome passage in context. Restrict Low/High frequency, then adjust
+Amount and Max cut. Sensitivity is a prominence threshold: lower catches more.
+Neighborhood defines the spectral reference; Cut width smooths the attenuation.
+Attack and Release smooth gain changes; Transient guard briefly relaxes cuts.
+
+Double-click the plot to add one of four focus points. Positive sensitivity
+makes the detector more eager; negative values protect the region by raising
+the threshold. Drag a point, wheel to change width, or use its numeric fields.
+Range boundary handles constrain where processing may act. Focus is detector
+weighting, not a static EQ boost and not an absolute protection guarantee.
+
+Cyan shows spectral input energy, coral the attenuation, violet detector focus.
+The left scale is calibrated per-bin spectral power; the right scale is cut dB.
+Delta plays delayed dry minus wet before output trim. Use it to inspect changes,
+then return to normal monitoring to decide whether the music improved.
+Mix is a linear blend of aligned signals. Bypass keeps the same latency.
+Use Output for matched-level comparison. Spectral attenuation is not a limiter:
+sample peaks can increase even when frequency gains never exceed unity.
+
+Four starting presets and A/B comparison help explore alternatives. All controls
+are visible. The instrument-style sidebar holds Amount, Mix, and Output; the
+spectrum includes filled energy traces, cut overlays, meter rails, and range
+handles, using the plugin’s cyan/coral/violet palette. Host parameters and window size persist; Delta does not. The editor
+supports numeric entry, keyboard focus, and direct graph editing.
+
+## Timing and limits
+
+Mixing only: 4096-sample analysis windows at 44.1/48 kHz, 8192 at 88.2/96 kHz,
+16384 at 176.4/192 kHz, with eight overlaps. Delay is one window, about 85–93 ms.
+The plugin reports it for host compensation. Supported layouts are mono and
+linked stereo; supported rates are those six standard rates.
+
+The engine uses complex RustFFT with supplied scratch buffers, WOLA reconstruction,
+a log-frequency prominence detector, bounded soft-knee cuts, and temporal/frequency
+smoothing. Original bin phases are retained. This is not a minimum-phase filter
+bank, a live monitoring effect, a limiter, or an automatic separation of tone and
+unwanted resonance. No external sidechain, Learn, M/S, or pitch detector in v0.1.
+
+## Build and offline evaluation
+
+```sh
+cargo test --workspace --locked
+cargo run --release -p resonance-render -- input.wav processed.wav
+cargo run --release -p resonance-render -- input.wav delta.wav --delta
+cargo run --release -p resonance-render -- --demo /tmp/resonance-demo.wav
+cargo run --release -p resonance-render -- --benchmark
+python scripts/build-plugin.py --plugin resonance-compressor --target x86_64-pc-windows-gnu
+```
+
+The renderer accepts mono/stereo PCM16/24/32 and float32 RIFF/WAVE, capped at
+256 MiB; WAV extensible/RF64 are not accepted. It writes float32 WAV, compensates
+the processing delay, retains original duration, and refuses existing output.
+An optional settings JSON uses the core's Settings structure.
+
+## CI and acceptance
+
+The root GitLab pipeline runs checks in a Linux Docker executor and cross-builds
+**Windows binaries only** using MinGW. It needs an available untagged Docker
+runner, outbound access to Debian/Rust/Cargo/Git dependencies, and no Windows
+runner. The Windows job produces both CLAPs, setup guides, licenses, checksums,
+and a ZIP. Runner execution must be verified on the actual GitLab instance;
+local verification is not a remote pipeline run.
+
+Before calling host support complete, test FL Studio discovery as an effect,
+automation, plugin delay compensation, parallel dry/wet alignment, repeated loading,
+project restoration, mono/stereo, all supported sample rates, and render tails.
+Judge through real patches with matched listening levels: preserve vowel motion,
+snare punch, bass body, and stereo placement. Synthetic tests do not establish
+artistic usefulness.
+
+Local benchmark: AMD Ryzen 7 PRO 3700U, optimized build, stereo 48 kHz, FFT
+4096/hop 512: five seconds processed in 0.233 seconds (about 4.7% of one
+core in that run). This is not a worst-case multi-instance guarantee.