docs: refresh wp.org readme copy and clean up changelog formatting

[arifulhoque7]

Refreshes the wp.org listing copy (plugin title, short description, Description body) and fixes formatting the wp.org readme parser mishandles.

Changes

• Section levels — Why Choose User Frontend and Perfect for Building demoted from == to =. As == they were parsed as separate top-level readme sections rather than Description subheadings.
• Inline bold — normalised <strong> to Markdown **, matching the style already used in the Pro feature list.
• Stray heading — removed the empty = = heading before Screenshots.
• Changelog headings — dropped the v prefix (= v4.3.10 = → = 4.3.10 =) so headings match the released version numbers.
• Changelog accuracy — 4.0.1/4.0.2/4.0.3 and 4.2.8 duplicated the entries of the release before them; collapsed into re-release notes. Fixed the escaped-emoji markup in the 4.1.8 typo entry.
• Copy — external-services descriptions now describe WPUF's AI form generation instead of the project/task wording carried over from another plugin; corrected the Anthropic ToS link; fixed shortcdoe and main compatibility typos.
• Added the missing trailing newline.

Short description is 141 chars (under the 150 limit). No ## Markdown headers, no CRLF.

Notes

• No functional changes — readme.txt only.
• The same content is being pushed directly to wp.org SVN (trunk + tags/4.3.10) so the live listing updates without waiting for a release; the wp.org page serves tags/<Stable tag>/readme.txt.