Switch hand ranges to Poker Skill's 6-max charts with 3bet/call frames

- Replace the Yokosawa ranges with the 6-max opening ranges (UTG, HJ, CO,
  SB, BTN). Colors keep the old order: navy (strong UTG), red UTG, yellow
  HJ, green CO, blue SB, white BTN. SB is narrower than BTN, so blue sits
  one tier above white; the purple-frame category is gone.
- Show the "BTN vs CO open" chart on the range page as frames: light blue
  for 3bet, yellow for call.
- Grade BTN facing an unlimped CO open by those frames in reviews; other
  spots keep the color-tier rule (BB defends down to green).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

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