Clean up how we use links

[rchlfryn]

Description

This PR cleans up for we use Button and CMSLink components. We currently use buttons in 3 different ways:

1. CMSLink - a guided way for a user to choose a link form a collection. Looks like a button but is rendered as an a tag
2. Link + Button - a link to another page or action
3. Button - not a link but performs an action

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From the linked issue:

This issue should consider the best approach to using links with button styling that also capture events.

I assume the second part of this is referring to Posthog events. All link clicks are autocaptured by posthog.

Related Issues

Resolves #685
Resolves #753

Key Changes

• Add ButtonLink component and consolidates CMSLink to ButtonLink since we were repeating the components pattern
• Removed unused button variants destructive and link
• Updated EventTable and EventPreview to use proper Button component instead of incorrectly used CMSLink
• Adds clearIrrelevantLinkValues to linkField
• Refactors linkToPageOrPost to linkField
  • Needed to keep linkToPageOrPost for quickLinks config since the type is array instead of group
• Clean up defaultLexical url validation
• Updated coding guide

How to test

There should be no visual differences

Migration

Rename button_appearance to button_variant

Future enhancements / Questions

We could use linkField in navLink, since the configs are identical. Using linkField will change newTab to be the second column which will cause a migration that will create a new table and drop the old one which seems invasive for the change. Do we want to do this?

[github-actions]

Preview deployment: https://link-cleanup.preview.avy-fx.org

[github-actions]

Migration Safety Check

Found 8 potential issues:

20260128_213937_rename_appearance_to_variant.ts

Warning (line 6): ALTER keyword detected - review for data loss

sql`ALTER TABLE \`home_pages_blocks_link_preview_cards\` RENAME COLUMN "button_appearance" TO "button_variant";`,

Warning (line 6): RENAME keyword detected - review for data loss

sql`ALTER TABLE \`home_pages_blocks_link_preview_cards\` RENAME COLUMN "button_appearance" TO "button_variant";`,

Warning (line 9): ALTER keyword detected - review for data loss

sql`ALTER TABLE \`_home_pages_v_blocks_link_preview_cards\` RENAME COLUMN "button_appearance" TO "button_variant";`,

Warning (line 9): RENAME keyword detected - review for data loss

sql`ALTER TABLE \`_home_pages_v_blocks_link_preview_cards\` RENAME COLUMN "button_appearance" TO "button_variant";`,

Warning (line 12): ALTER keyword detected - review for data loss

sql`ALTER TABLE \`pages_blocks_link_preview_cards\` RENAME COLUMN "button_appearance" TO "button_variant";`,

Warning (line 12): RENAME keyword detected - review for data loss

sql`ALTER TABLE \`pages_blocks_link_preview_cards\` RENAME COLUMN "button_appearance" TO "button_variant";`,

Warning (line 15): ALTER keyword detected - review for data loss

sql`ALTER TABLE \`_pages_v_blocks_link_preview_cards\` RENAME COLUMN "button_appearance" TO "button_variant";`,

Warning (line 15): RENAME keyword detected - review for data loss

sql`ALTER TABLE \`_pages_v_blocks_link_preview_cards\` RENAME COLUMN "button_appearance" TO "button_variant";`,

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Review these patterns and add backup/restore logic if needed. See docs/migration-safety.md for guidance.