schwung-chiptune

Help text corrections only. No DSP changes.

• Channel Mask and Detune are not editable. Help wrote them up as user controls; neither key appears in any ui_hierarchy level, only in chain_params. They are fixed by the preset. Help now says so.
• Documented Sweep (0-7, GB pulse 1 only; 0 = off, higher values sweep the pitch up more slowly) — reachable but previously undocumented.
• Documented Noise Mode (Long = full LFSR hiss, Short = short LFSR, metallic; applies to both NES and GB noise).

Chiptune was running 6x hot and clipping.

Both render paths multiplied the APU output by a hardcoded 6, on the strength of a comment reading "NES APU output peaks ~5000; 6x scales to ~30000 for good headroom within int16 range." The premise was wrong: the APU peaks around 7,300 for a single voice and ~19,000 on a poly preset, so 6x did not scale into headroom, it scaled into the ceiling.

• 26 of the 32 presets peaked at 0.0 dBFS, and the clipping was not incidental — GB Unison clipped 21,908 of 51,200 samples (43%), NES Unison 19,488. That distortion had become part of what those presets sound like.
• Against its neighbours, chiptune sat 13-17 dB hot: RMS -1.5..-8 dBFS, versus -40..-18 dBFS across all 48 Braids engines and -21.9 dBFS for Open303.
• At unity the same sweep gives RMS -13.7..-23 dBFS and a worst-case peak of -4.74 dBFS (GB Poly, five notes held), with zero clipped samples in any preset. The clamps stay as a backstop rather than the operating point.

Chiptune will be noticeably quieter in existing sets — roughly 15 dB. That is the fix, but you may want to raise its slot volume in projects that already use it.

• Add short_name to parameters for the Schwung knob grid
• chore: update license to MIT
• Update docs: rename Move Anything references to Move Everything
• Update release.json URL for repo rename

• Fix envelope release/decay - voices now stay active through release phase