Felt Orbit v28 - ORAC native Manta page test

Based on the confirmed v24 audio/control build.

Reference implementation:
- uploaded Oscilloscope 1.5
- uploaded Cycles 1.5

Changes:
- module.json now declares a second Orac page:
    pg_felt_visual / Manta
- module.pd detects activePage exactly like the reference modules:
    unpack s s
    first symbol -> sel $1
    second symbol -> sel pg_felt_visual
    both must be active
- OLED messages use oscOutRaw, not oscOut.
- On the Manta page the info bar is hidden.
- A static manta is redrawn every 120 ms using gClear -> gLine -> gFlip.
- Leaving the Manta page stops the redraw and restores the info bar.

No audio DSP, sample loading, latch, release, pitch, or parameter code was changed.
This is intentionally a static graphics/page-routing test.
