Example enc4: flash white-out (m_flFlashMaxAlpha + m_flFlashDuration) as the float demo

enc4 should exercise a float encoder, and m_iDesiredFOV is a uint. Use the two
networked flash floats instead: m_flFlashMaxAlpha (intensity 0..255) +
m_flFlashDuration (hold/fade seconds). Spoofing both white-outs every client —
a genuinely float-encoded, unmistakably visible demo. No networked flash
start-time field exists; the client begins the flash when the duration netvar
changes, so the spoof (0 -> 5) triggers it.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>