feat: AnaMark .tun microtuning (Load / Reset / host state)

[Megagoth1702]

Summary

Adds AnaMark .tun microtuning support to JC-303:

• Load a .tun file into a validated 128-note Hz table
• Reset to 12-TET (from the TUNING / A4 knob)
• Show the active scale name in the amadeusp GUI while a custom map is loaded
• Persist custom tuning with host/plugin state (absolute frequencies; original file not required later)
• Fail closed on invalid / incomplete .tun content, with a line-level error dialog (no silent accept)

UI

Controls sit under the Tuning knob (above the MOD strip) inside the existing 930×363 amadeusp skin (no editor size change).

State	What you see
12-TET (default)	Load only, centered under the Tuning knob
Custom scale loaded	[Reset] left · [Load] center · scale name right

While a custom map is active:

• Reset and the scale name become visible
• The Tuning knob is disabled and dimmed until Reset (A4 fine-tune applies to 12-TET only)
• Failed loads keep the previous map and show “Tuning load failed” with filename + specific error (often including line number)

Behaviour / formats

Supported: AnaMark .tun v2 only (no Scala .scl / .kbm, no MTS-ESP).

Section	Policy
[Exact Tuning] present	Authoritative. Requires valid BaseFreq + all 128 Note n = <cents>. Non-numeric / incomplete → error. No fallback to Functional if Exact is present but broken.
Functional only (no Exact)	InitEqual = (refNote, refHz) seeds 12-TET; optional Note T = "#=B %C" overrides in file order (base chaining). Malformed lines → error, not silent skip.

Conversion: cents → Hz via f = BaseFreq * 2^(cents/1200) (Exact) or chained Functional bases.

Technical notes

• No new third-party deps. In-house pure C++ loader: src/dsp/tuning/ (TuningTable, TuningFileLoader, smoke test).
• Single pitch path in Open303: note-on / slide / release always use noteToHz() against a double-buffered 128-entry bank (installPitchMap). ET is just another full map.
• Ownership: JC303 owns custom vs ET policy, host XML, UI notifications; Open303 stays policy-free (master A4 + banks only).
• TUNING knob: always updates master A4; rebuilds live 12-TET only when custom is inactive; does not rewrite custom absolute frequencies.
• Host state: APVTS child CustomTuning (active, name, freqs CSV of 128 Hz, optional path). Malformed payloads fall back to clean 12-TET.
• LFO (from develop): destinations filter / volume / pitch still apply in getSample. Pitch LFO is a frequency multiplier on oscFreq after table lookup + slew — works with custom maps and 12-TET.
• Optional CMake overrides keep stock defaults for upstream (JC303 / J303, full format set); private builds may pass -DJC303_PRODUCT_NAME=…, -DJC303_PLUGIN_CODE=…, -DPLUGIN_FORMATS=….
• amadeusp only — midilab theme has no Load/Reset bar yet.

Testing

• VST3 Release build on Windows (VS / CMake) after merge with develop — BUILD OK
• Load valid AnaMark .tun → scale name + audible pitch change
• Reset → 12-TET, Tuning knob re-enabled
• Host state save/recall of custom map
• Invalid files rejected with dialog (manual: deleted Exact lines, letters where numbers belong — previously silently accepted)
• Standalone smoke test: src/dsp/tuning/tuning_smoke_test.cpp
  Covers Exact complete/incomplete/non-numeric, bad BaseFreq/InitEqual, no Exact→Functional fallback, Functional init/override/chain/garbage, CSV round-trip, validation — all passed after develop merge

Out of scope / known limits

• midilab GUI theme: no Load/Reset bar (amadeusp only for v1)
• No Scala .scl / .kbm
• No MTS-ESP
• No in-plugin scale editor / skin redesign
• LFO UI on amadeusp/midilab is whatever develop already ships (this PR does not add LFO widgets)

Merge note for maintainers

• Branch includes current develop (merge commit 0597f0c). Merging this PR into develop should be conflict-free at tip 8e16c3e.
• Integration: CMake lists both dfl_LFO.cpp and TuningFileLoader.cpp; Open303 includes both dfl_LFO.h and TuningTable.h.

[dfl]

noice! 🤘