fix(studio): parse modern CSS colors in the inspector and gradient editor

[dkryaklin]

Problem

Select an element styled with color: oklch(0.7 0.15 200) in Studio. The inspector swatch shows black. Drag the picker and the element turns black.

parseCssColor in packages/studio/src/components/editor/colorValue.ts only read hex and comma-separated rgb(). That is not what reaches it:

• getComputedStyle keeps oklch(), oklab() and lab() as written, and turns color-mix() into color(srgb ...).
• Gradient stops are read from the authored background-image, so white, #0f172acc or rgb(255 0 0 / 50%) are common there.

All of these returned null. The inspector fell back to black. In the gradient editor a stop inserted between two named stops copied its left neighbour instead of blending.

Fix

• parseCssColor parses with @colordx/core plus its named-color plugin. It covers CSS Color 4, has no dependencies, is 8.4 KB gzipped, and is the fastest parser in its class.
• gradientValue.ts drops its own parser and uses parseCssColor.
• InlineTextToolbar.tsx drops its canvas fallback, which only existed for named colors.

Verification

• colorValue.test.ts: modern computed colors, named colors, 8-digit hex, gamut clipping, rejected input, picker hex conversion.
• gradientValue.test.ts: interpolation across named stops and across 8-digit hex stops with alpha.
• bun run --cwd packages/studio test: 428 files, 4786 passed.
• oxlint, oxfmt --check, tsc --noEmit clean. bun install --frozen-lockfile accepts the lockfile.

[miguel-heygen]

@dkryaklin sign the commit to merge it pls

[dkryaklin]

@dkryaklin sign the commit to merge it pls

Done 👍

[dkryaklin]

@dkryaklin sign the commit to merge it pls

Friendly ping

[jrusso1020]

Thanks for identifying this and adding regression tests. We'd prefer to avoid a new runtime dependency for color parsing. We prototyped a browser-native approach in #3931—could you adapt that into this PR while keeping the regression coverage?

[dkryaklin]

Thanks for identifying this and adding regression tests. We'd prefer to avoid a new runtime dependency for color parsing. We prototyped a browser-native approach in #3931—could you adapt that into this PR while keeping the regression coverage?

Sure, no problem. I've updated the PR with your approach from #3931 and kept my gradient test