Add edit support to Comments v2

[crazytonyli]

Description

This PR lets moderators edit approved, pending, spam, and trashed comments from the detail screen. CommentComposerView reuses the reply composer with edit-specific labels, validation, errors, and discard handling.

Successful edits update the open detail screen and loaded list rows through CommentChangeEvent.contentChanged. CommentsModerationCoordinator serializes edits with other mutations on the same comment.

A timeout after the server saves an edit can still show an error. Retrying sends the latest text again because WordPress treats comment edits as last-writer-wins updates.

Testing instructions

• Enable Comments v2 and sign in to a self-hosted site with an application password.
• Open an approved or pending comment, tap More, then Edit. Verify the editor contains the original content and Save stays disabled until the text changes.
• Save a change. Verify the detail screen updates, then return to the list and verify its snippet updates.
• Change the content again, then cancel. Verify you can keep editing or discard the changes.
• Verify Spam and Trash comments can be edited.
• Disconnect the network before saving. Verify the editor stays open with an error, then reconnect and retry.
• Verify replying and saving or deleting reply drafts still work.

[dangermattic]

	2 Warnings
⚠️	View files have been modified, but no screenshot or video is included in the pull request. Consider adding some for clarity.
⚠️	This PR is larger than 500 lines of changes. Please consider splitting it into smaller PRs for easier and faster reviews.

	1 Message
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	App Name	WordPress
	Configuration	Release-Alpha
	Build Number	34341
	Version	PR #25958
	Bundle ID	org.wordpress.alpha
	Commit	a968261
	Installation URL	2qn12v7c2ob10

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	App Name	Jetpack
	Configuration	Release-Alpha
	Build Number	34341
	Version	PR #25958
	Bundle ID	com.jetpack.alpha
	Commit	a968261
	Installation URL	5ikdgkv5sdni8

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