feat(skill): boost Steel Teal visibility in background compositions

Steel Teal (#477E96) was at opacity 0.38-0.45 — barely visible.
- Corner Warmth: moved to lower-center (cx=0.42, cy=0.62), opacity 0.38 → 0.68
- Deep Space: moved to upper-center sweep (cx=0.34, cy=0.30), opacity 0.45 → 0.72
Steel Teal now reads as a distinct blue-grey band in both compositions.

Signed-off-by: Lee Calcote <lee.calcote@layer5.io>

Author: leecalcote