chore: fixed rule tags

[mattscepter]

<< Describe the changes >>

Closes:

[Copilot]

Pull request overview

This pull request updates rule tags for experimental accessibility rules by removing the standalone "experimental" tag and adding three new tags: "a11y-engine", "a11y-engine-experimental", and "medium-accuracy". This change standardizes the tagging approach for experimental rules across the accessibility rule engine.

Key changes:

• Removed the generic "experimental" tag from five rule configuration files
• Added three new tags ("a11y-engine", "a11y-engine-experimental", "medium-accuracy") to replace the experimental tag
• Reformatted one rule file (hidden-content.json) to maintain consistent JSON structure

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
lib/rules/td-has-header.json	Replaced "experimental" with three new tags for the table header validation rule
lib/rules/table-fake-caption.json	Replaced "experimental" with three new tags for the table caption validation rule
lib/rules/hidden-content.json	Replaced "experimental" with three new tags and reformatted tags array from single-line to multi-line
lib/rules/focus-order-semantics.json	Replaced "experimental" with three new tags for the focus order validation rule
lib/rules/css-orientation-lock.json	Replaced "experimental" with three new tags for the CSS orientation lock validation rule

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[rohitsahu-bstack]

lgtm, pending @Abhi3685 approval