refactor: simplify YoastLlmsTxt by merging duplicate rewrite methods

[jdevalk]

Summary

• Removes rewrite_page_link, which was functionally identical to rewrite_post_link — same body, same logic, different parameter name only
• Routes the page_link filter to rewrite_post_link instead, since get_post_type() accepts both a WP_Post object and an integer post ID
• Updates the rewrite_post_link docblock to reflect that it now handles all three permalink filters (post_link, page_link, post_type_link)

Test plan

• Verify page URLs get .md appended during llms.txt generation
• Verify post URLs get .md appended during llms.txt generation
• Verify CPT URLs get .md appended during llms.txt generation
• Confirm all three filters are properly removed after stop() is called (no filter leakage)

🤖 Generated with Claude Code

[Copilot]

Pull request overview

Refactors the Yoast llms.txt integration to reduce duplication by using a single permalink rewrite method for posts, pages, and CPTs during Yoast’s llms.txt generation flow.

Changes:

• Replaced repeated add_action calls with a foreach loop over Yoast regeneration triggers.
• Routed the page_link filter to rewrite_post_link and removed the duplicate rewrite_page_link method.
• Updated rewrite_post_link docblock to reflect its broader usage and accepted parameter types.

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[Copilot]

update_option_wpseo / update_option_wpseo_llmstxt are core update_option_{$option} actions that pass arguments (old value, new value, option). With add_action(..., 9) the default accepted args is 1, so WordPress will pass an argument into start()/stop() which declare no parameters; this will throw an ArgumentCountError on PHP 8+. Fix by setting accepted args to 0 in these add_action calls, or update start/stop signatures to accept (and ignore) the incoming args.

Suggested change

	add_action( $action, [ $this, 'start' ], 9 );
	add_action( $action, [ $this, 'stop' ], 11 );
	add_action( $action, [ $this, 'start' ], 9, 0 );
	add_action( $action, [ $this, 'stop' ], 11, 0 );