docs: rename skip link anchor #_top → #main-content (WCAG 2.4.1)

[Copilot]

The docs skip link targeted #_top — an anchor name that implies "top of page" rather than "main content", violating WCAG 2.4.1 naming clarity. Starlight doesn't expose a stable id on <main>, so the fix requires both a new anchor target and a script to create it.

Changes

• SkipLink.astro — href="#_top" → href="#main-content"
• scripts/skip-link.ts (new) — sets id="main-content" and tabindex="-1" on Starlight's <main> element; re-runs on astro:page-load to cover client-side navigation
• CustomHead.astro — imports skip-link.ts alongside the existing search-aria and copy-button-aria enhancement scripts

The tabindex="-1" makes <main> programmatically focusable without inserting it into the natural tab order.

[Copilot]

Pull request overview

Updates the docs “skip to main content” link to target a clearer anchor (#main-content) for WCAG 2.4.1 naming clarity, and adds a small client-side enhancement to ensure the target exists on Starlight pages.

Changes:

• Update the skip link target from #_top to #main-content.
• Add a new script that assigns id="main-content" (and tabindex="-1") to the page’s <main> element, including on astro:page-load.
• Load the new skip-link enhancement script via CustomHead.astro.

Show a summary per file

File	Description
docs/src/scripts/skip-link.ts	New script to create a stable skip-link target on <main> and make it focusable.
docs/src/components/SkipLink.astro	Changes skip link href to #main-content.
docs/src/components/CustomHead.astro	Loads the new skip-link enhancement script site-wide.

Copilot's findings

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Comments suppressed due to low confidence (1)

docs/src/scripts/skip-link.ts:27

• SkipLink now targets #main-content, but this script only sets main.id = 'main-content' when <main> has no existing id. If Starlight (or another integration) adds a different id to <main> in the future, #main-content will never exist and the skip link will break. Consider ensuring #main-content always exists (e.g., set the id unconditionally, or insert a dedicated anchor element with id="main-content" without overwriting an existing id).

	if (!main.id) {
		main.id = 'main-content';
	}

• Files reviewed: 3/3 changed files
• Comments generated: 1

[Copilot]

The docstring says the script “adds id="main-content" and tabindex="-1" to the <main> element”, but the implementation only adds them when the attributes are missing. Either update the comment to reflect the conditional behavior, or change the implementation to always enforce the expected target (#main-content).

This issue also appears on line 25 of the same file.

Suggested change

	* This script adds `id="main-content"` and `tabindex="-1"` to the `<main>`
	* element so that the skip link (`href="#main-content"`) lands on the correct
	* landmark and keyboard focus is reliably placed there. The `tabindex="-1"`
	* attribute makes the element programmatically focusable without including it
	* in the natural tab order.
	* This script ensures the `<main>` element has `id="main-content"` and
	* `tabindex="-1"` when those attributes are missing, so the skip link
	* (`href="#main-content"`) lands on the correct landmark and keyboard focus is
	* reliably placed there. The `tabindex="-1"` attribute makes the element
	* programmatically focusable without including it in the natural tab order.