fix: derive semantic theme tokens on the dashboard theme boundary - #9811

app.css declares the hover, accent, focus-ring, dimension and measure tokens on :root, against Rill's own primary/secondary palettes:

:root {
  --surface-hover: var(--color-primary-50);
  --popover-accent: var(--surface-hover);
  --ring-focus: var(--color-theme-300);
  /* ...accent-*, icon-accent, fg-accent, dimension-*, measure-* */
}

A custom property's var() references are substituted at the element that declares it, so these always resolve against the default palette. A dashboard theme is scoped to .dashboard-theme-boundary further down the tree, so it can never reach them — Rill's indigo leaks into hover, selection, focus rings and dimension/measure chips on a rethemed dashboard, even though --color-theme-* itself is correct.

• Re-declare the affected tokens on the boundary from the theme's own palettes. The shades mirror app.css exactly (PALETTE_DERIVED_TOKENS), so only the hue source changes, not the design.
• Dark mode keeps its neutral gray surfaces: surface-hover/surface-active/popover-accent are emitted as unset so the boundary inherits :root.dark. Dark accents read the light-palette shades, matching what :root.dark does.
• Alias --color-primary-* and --color-secondary-* to the theme's palettes inside the boundary, so the ~300 bg-primary-500-style utilities in dashboard components follow the theme without each one being migrated. Outside the boundary — nav, file explorer, admin chrome — Rill's brand colors are untouched.
• Explicit variables: in the theme YAML still win, and a theme that sets fg-primary keeps ownership of fg-accent.

Worth a look during review: this now themes the dimension and measure chips as well. That is the intended behaviour for brand adherence, but it is the most visible change beyond hover and selection.

Reported for explore leaderboards, where hover (bg-popover-accent) and excluded bars (var(--surface-active)) stayed purple under a custom theme. The fix is at the token level, so it clears the same leak in dropdowns, pivot rows, the TDD table and filter chips at the same time.

Checklist:

• Covered by tests
• Ran it and it works as intended
• Reviewed the diff before requesting a review
• Checked for unhandled edge cases
• Linked the issues it closes
• Checked if the docs need to be updated. If so, create a separate Linear DOCS issue
• Intend to cherry-pick into the release branch
• I'm proud of this work!