feat: operator Phase & Warp, mod-matrix destinations, CPU optimisation (v1.06f)

Operator Phase & Warp

• Add per-operator Warp parameter (±4 range, values beyond ±1 invert one
  half-cycle). Implemented in getNextSample / getNextBlock / getNextBlockHQ
  including the decimated sub-paths. A deadband near zero preserves the fast
  no-warp code path under near-zero modulation.
• Per-operator start Phase offset retained and wired; oscilloscope phase marker
  visualisation added (FirmwareTftDisplay).
• Patch format bumped to v1.5; Warp defaults to 0 on load of older patches,
  out-of-range values clamped on load (PreenFMFileType.cpp).

Modulation matrix

• New destinations OSC1..6_PHASE and OSC1..6_WARP added to DestinationEnum
  (Common.h).
• Phase applied at note-on; Warp updated every block in
  Voice::prepareMatrixForNewBlock via updateWarpWithMatrix (Voice.cpp / Osc.h).
• Matrix destination labels o1Ph–o6Ph and o1Wr–o6Wr wired in FMDisplayEditor.

MIDI

• CC_OSC1..6_WARP mapped per operator (MidiDecoder.cpp / MidiDecoder.h).
• ENCODER_OSC_WARP encoder row added to editor UI.

Synth engine / init

• Osc::init now receives phaseParamsBase pointer; each oscillator binds its
  Warp directly to its per-timbre phase row, fixing parameter ownership across
  timbres (Osc.cpp / Timbre.cpp / SynthState.cpp / SynthState.h).

CPU optimisation

• quantizeOscOutputBeforeEnvelope skipped in non-decimation block-render paths
  (getNextBlock, getNextBlockHQ, getNextSample), removing a branch + two
  multiplies per sample in the common case.
• waveDecimationEnabled cached once per block call instead of read per sample.
• Selective #pragma GCC optimize("Ofast","fast-math") applied in Release builds
  only to six hot DSP translation units: Osc.cpp, Voice.cpp, FxBus.cpp,
  TimbreFx.cpp, SimpleComp.cpp, SimpleEnvelope.cpp.
• Release makefile: -O2 for DebugLQFP144; LTO enabled for Release link.

Versioning

• firmware version bumped to v1.06f (version.h).

Documentation

• README.md updated with full description of Phase, Warp, mod-matrix
  destinations, CPU optimisation, and patch migration notes.