Add Range plugin for track fill, value bubble, and tick marks

[mdo]

Summary

Adds an opt-in JavaScript plugin that enhances <input type="range">, building on the idea from #37499 and taking it further into a proper plugin.

A consistent cross-browser fill cannot be done with pseudo-elements alone — only Firefox has ::-moz-range-progress; WebKit/Blink have no equivalent and CSS can't read an input's value. So the plugin publishes the current value as a --bs-range-value custom property that the track gradient consumes.

Opt in per input with data-bs-range; plain .form-range inputs are completely unaffected.

Features

• Fill — colored track up to the thumb, themeable via --range-fill-bg.
• Value bubble (data-bs-bubble="true") — a floating value that tracks the thumb.
• Tick marks (data-bs-ticks="true") — generated from a linked <datalist>, with labels from each <option>.

Options: bubble, ticks, formatter. Emits changed.bs.range.

Notes

• The bubble and tick marks are siblings of the input, so they don't inherit the input's --range-fill-bg token. The plugin copies the input's resolved fill color onto them, and the CSS falls back to --primary-base, so they're never rendered blank. (This was the cause of an invisible bubble in early testing.)
• input isn't in EventHandler's native-event list, so it can't be namespaced — it's bound raw and removed explicitly in dispose().
• The input is intentionally not wrapped (wrapping would break validation's .form-range ~ .invalid-feedback); instead the parent gets a .range-anchored positioning class and decorations position from the input's offset box.

Test plan

• New js/tests/unit/range.spec.js; full Karma suite passes (1113/1113).
• Verified rendering in WebKit (Playwright) — fill, bubble, and ticks all render correctly.
• ESLint, Stylelint, markdownlint, and Prettier all clean.

dist/ is intentionally not committed here; CI rebuilds it.