[2dubu]

What changed

• Add focused DocC guides for choosing an extraction result, image input workflows, Display P3 and OKLCH behavior, and common questions.
• Reorganize the DocC landing page and existing tutorials around developer tasks and search intent.
• Correct documentation for sRGB output boundaries, Metal selection, downsampling, remote image loading, result reuse, performance measurement, and accessibility validation.
• Expand public symbol documentation for extraction sources, color-space modes, and UI adapters.
• Leave README.md and runtime behavior unchanged.

Why

PaletteKit already exposes the relevant APIs, but several implementation boundaries were either difficult to discover or described too broadly. The new structure gives developers direct, citable answers while keeping claims aligned with the implementation.

Developer impact

Documentation-only and public documentation-comment changes. No runtime API or behavior changes.

Validation

• DocC conversion with --warnings-as-errors
• PaletteExtractorTests: 8/8 passed
• git diff --check