# ALPHA50.9.24 — rasterizer-safe spatial color bands

## Scope
Replace the `radialGradient` rendering path introduced by Alpha.50.9.23 after staging QA showed that ImageMagick rasterization turns the large gradient regions nearly black. Keep the established spatial color allocator and region geometry, but render oversized regions with ordinary SVG clipping plus concentric solid-color circles.

## Behavior
- Keep the existing 10-color master palette and the existing character / n-gram profile model.
- Keep the seven profile-derived regional colors and the v9 spatial allocation strategy.
- Upgrade the persisted mapping to `chat-profile-v10-spatial-region-banded` so existing v3-v9 games regenerate their spatial descriptors on status read.
- Preserve spatial styles inside the existing `unit_colors_json` payload under `__region_spatial_styles`; no new database column or migration is required.
- For oversized regions, render deterministic concentric solid-color bands clipped to the existing region path.
- Do not use SVG `radialGradient`/`stop` elements in the Chat Mandala renderer.
- Keep source SVG geometry, region segmentation, reveal progression, Structure/Energy, Telegram transport and localization unchanged.

## QA finding addressed
Alpha.50.9.23 reached staging and was checked against the existing active game #3. The API returned `chat-profile-v9-spatial-region-distributed` with five spatial styles, but the generated VPS PNG had approximately 56.27% near-black pixels. Rendering the same SVG with ordinary solid fills reduced the near-black fraction to approximately 0.12%, proving the rasterizer failure was specific to the SVG radial-gradient path.

## Acceptance
- No `radialGradient` is generated by the renderer.
- Oversized spatial styles contain at least three palette colors and deterministic concentric band radii.
- Existing active games regenerate to v10 on status read.
- Automated Structure/JS/Unit/Integration/API checks pass.
- The same existing staging game can render to PNG without the previous gradient-induced near-black mass.