D9Label help text is easier to read and has an id (<id>-help); D9Select passes aria-describedby to its button

[PhilReinking]

D9Label's help text is now readable, and a field can point at it with aria-describedby. The help text gets the id <id>-help (none without an id) and the color grey-500. Contrast is 4.76:1 on white and 4.55:1 on grey-50 (before: 2.56:1 and 2.45:1).

• New story "Forms/Label → Linked to field" shows aria-describedby="name-help" on a D9Input.
• D9Select now puts aria-describedby on its button. class, style, data-* and other attrs stay on the wrapper as before.

Fixes BITS-289

Tested: check, lint, test, build pass; the new Label and Select specs fail on main. Headless Brave accessibility tree reads the help text for Input, Textarea and Select.

After merge: Input needs an @deck9/ui bump and aria-describedby="<id>-help" on its fields.

🤖 Generated with Claude Code

[PhilReinking]

OK at 1ed38aa, CI green. Help text is 4.76:1 on white and 4.55:1 on grey-50 (dark: 5.71:1 on grey-800). Packed .d.ts files match main. class and id on D9Select land where they did; Input's calls don't change. Headless Chrome reads the help text as the Select button's description. One should inline. The title could also name the D9Select fix: "…; D9Select passes aria-describedby to its button".

[PhilReinking]

A computed over useAttrs() only re-runs if it read an attr. If D9Select first renders with no attrs and gets a class later, the class never reaches the wrapper (on main it does). Make it a plain function and bind it as v-bind="wrapperAttrs()" on line 8.

Suggested change

	const wrapperAttrs = computed(() =>
	Object.fromEntries(
	Object.entries(attrs).filter(([name]) => name !== "aria-describedby")
	)
	);
	const wrapperAttrs = () =>
	Object.fromEntries(
	Object.entries(attrs).filter(([name]) => name !== "aria-describedby")
	);

[PhilReinking]

OK at fe3015b, CI green. The Select fix holds: a class or aria-describedby set after the first render now lands on the wrapper and the button. The new spec fails on 1ed38aa and passes here. npm test 16, check, lint, build pass. Packed .d.ts files still match main. Title names the D9Select change.