Add "Permalink" to the Slug editor and more

[kean]

Closes https://linear.app/a8c/issue/CMM-558/add-permalink-in-slug-editor-and-add-explanation-about-slug

• Add permalink preview to the slug editor. It is based on the new permalinkTemplateURL returned by the server and now included in the Core Data model for 25.6. It seems to be available only using the REST API, so it's Dotcom only.

  "other_URLs": {
    "permalink_URL": "https://test841027.wpcomstaging.com/2025/10/15/%postname%/",
    "suggested_slug": "test-discussion"
  }

• Add "Learn More" link
• Automatically lowercase characters you input and replace spaces with dashes

Screenshots

Before / After

[wpmobilebot]

📲 You can test the changes from this Pull Request in WordPress by scanning the QR code below to install the corresponding build.

	App Name	WordPress
	Configuration	Release-Alpha
	Build Number	29544
	Version	PR #24949
	Bundle ID	org.wordpress.alpha
	Commit	b1455a8
	Installation URL	53hq8bh9vn6sg

Automatticians: You can use our internal self-serve MC tool to give yourself access to those builds if needed.

[wpmobilebot]

📲 You can test the changes from this Pull Request in Jetpack by scanning the QR code below to install the corresponding build.

	App Name	Jetpack
	Configuration	Release-Alpha
	Build Number	29544
	Version	PR #24949
	Bundle ID	com.jetpack.alpha
	Commit	b1455a8
	Installation URL	2hlog023f3b6g

Automatticians: You can use our internal self-serve MC tool to give yourself access to those builds if needed.

[crazytonyli]

It's safe to force-unwrap here, since the value is hard-coded.

[kean]

Updated.

[sonarqubecloud]

Quality Gate passed

Issues
8 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud