dlssnr: multi-pass cost slider and matched residual transfer

[hhkbble]

Summary

• Spatial multi-pass Neural Rendering: Feature 1 stays 1:1 at render resolution, the model runs at a display-relative WorkingScale, then OS_Dx12 FSR1 enlarges to display.
• Matched residual transfer (now the default): encoded area downsample plus residual compose onto the full-res proxy, with optional additive HDR lift. Classic bilinear + UpgradeToneMap remains selectable.
• Inspect UI greys out combinations the shader ignores (Debug vs Compare/Capture/compose; Classic vs Debug 4/5; additive lift vs Colour strength) and keeps stored INI values.

Test plan

• Fresh INI / missing Transfer key opens as Matched residual; existing Transfer=0 stays Classic.
• Toggle Classic ↔ Matched at WorkingScale 0.67: picture changes, no feature rebuild.
• Toggle at WorkingScale 1.0: no visible difference; combo stays enabled.
• Strength 0 + Compare off + Debug off: output matches hdrCopy.
• Debug view on: Compare, Capture, Detail/Colour/HDR lift disabled; Classic cannot select Full-res proxy / Matched picture.
• Multi-pass cost slider: time scales with display², Feature 1 stays 1:1.
• Host fixture area_fixture still prints TA PASS.