[WIP] Add support for Oklab, OkHSV, and OkLCH color spaces

[Copilot]

• Explore existing colorlib.rb code and reference implementation
• Set up linting baseline (rubocop passes)
• Implement OklabColor class (Data.define(:l, :a, :b)) with conversions to/from linear sRGB
• Implement OkLCHColor class (Data.define(:l, :c, :h)) with conversions to/from Oklab
• Implement OkHSV helper functions (toe, toe_inv, compute_max_saturation, find_cusp, etc.)
• Implement OkHSVColor class (Data.define(:h, :s, :v)) with conversions to/from sRGB
• Add to_oklab method to SRGBLinearColor
• Add to_oklab, to_oklch, to_okhsv convenience methods to SRGBColor
• Update RBS type signatures in sig/lib/qbot/colorlib.rbs
• Run rubocop and fix any offenses
• Verify conversions with a quick Ruby script (roundtrip tests)
• Run code_review and codeql_checker

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