ux: Tier 1 cleanup of wp_notes_page_callback — single H1, collapse triple welcome surfaces, footer support link

Single-pass UX cleanup of the main WP Notes admin page. Functionality
unchanged; the page is shorter, has one H1, and stops contradicting
itself.

CHANGES
- Single H1 on the page (was five different H1s).
- Welcome/about content collapsed from THREE on-page surfaces (top
  dismissible notice + nested toggle + Show/Close button row) to one
  single description line linking to the dedicated About page where
  the long copy already lives.
- Two duplicate "Toggle Welcome Section" buttons with the SAME label
  but different targets — both removed.
- Embedded "What's New v3.0.0" changelog block deleted: it was
  hard-coded to v3.0.0 while the plugin reports v3.0.2. The real
  history is in CHANGELOG.md.
- "Buy me a coffee" button moved from page header to page footer —
  promo shouldn't be the first thing under the page title.
- Invalid HTML cleaned up (li outside ul, p wrapping div/ul) by way
  of removing the welcome blob that contained it.
- Dead bulk-action UI removed: per-row checkboxes and "Select all"
  header in both wp_notes_display_notes() and wp_notes_list_table()
  rendered but nothing acted on the selection. Removed with inline
  comments marking the spot for when real bulk-actions land. Edit
  form colspan adjusted to match the new column count.
- ~80 lines of inline style+script for the about-box dismissal
  removed (localStorage tracking, show/hide handlers, two style
  blocks). WordPress's notice notice-info is-dismissible + user-meta
  is the right path if a banner needs to return.
- toggleSection() JS helper removed (no toggles remain).
- Small CSS additions to inc/wp-notes-styles.php for the header
  banner and footer-support link.

ALSO FIXED
- PHP 8.2 deprecation: ${size}px → {$size}px in the dashboard
  list-table render. ${var} interpolation is deprecated since 8.2
  and will hard-error in 9.0.

NET DIFF: wp-notes.php -213 lines, total -111 lines across 4 files
(plus a new CHANGELOG entry). Storage model unchanged.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

CHANGELOG.md

@@ -7,6 +7,66 @@ Format: [Keep a Changelog 1.1.0](https://keepachangelog.com/en/1.1.0/) — versi
 
 ## [Unreleased]
 
+### Changed — Tier 1 UX cleanup
+Single pass through `wp_notes_page_callback()` to remove the layout
+debt that had built up over previous releases. Functionality is
+unchanged; the page is shorter, has one H1, and stops contradicting
+itself.
+
+- **Single H1** on the page — was five (`Welcome to WP Notes`,
+  `Welcome to WP Notes v3.0.2`, `About WP Notes`, `What WP Notes
+  Offers`, `What's New in WP Notes v3.0.2`). Now: just
+  `WP Notes` with the version chip alongside. Accessibility + SEO.
+- **"Welcome / About" content** collapsed from THREE on-page
+  surfaces (a dismissible top notice + a nested toggle + a manual
+  "Show Welcome Message" button) down to a single one-line
+  description that links to the dedicated About page where the long
+  copy already lives.
+- **Duplicate "Toggle Welcome Section" buttons removed.** Both
+  outer and inner toggle buttons had the **same label** but
+  different targets — genuinely confusing. Both gone.
+- **"What's New v3.0.0" embedded changelog block removed.** It was
+  hard-coded to v3.0.0 while the plugin reports v3.0.2 — the embed
+  was lying. The real history lives in `CHANGELOG.md` now.
+- **"Buy me a coffee" button moved from page header to page footer**
+  — promo content should not be the first thing under the page
+  title. Now sits at the bottom of the notes lists, centred, where
+  footer items belong.
+- **Invalid HTML cleaned up** — `<li>` tags outside `<ul>`, `<p>`
+  tags wrapping `<div>` / `<ul>`. Was in the deleted welcome blob,
+  so resolved by removal.
+- **Dead bulk-action UI removed** — both the per-row checkboxes and
+  the "Select all" header column in `wp_notes_display_notes()` and
+  `wp_notes_list_table()` were rendered but nothing acted on the
+  selection. Removed both, with an inline comment marking the spot
+  for when real bulk-actions get wired up. Edit-form colspan
+  adjusted (`6` → `4`) to match the new column count.
+- **Inline `<style>` and `<script>` blocks for the dismissed
+  about-box** (~80 lines of localStorage-based dismiss tracking and
+  show/hide logic) **deleted** along with the about-box itself —
+  WordPress's own `notice notice-info is-dismissible` and the
+  user-meta dismissal API are the correct path if a banner needs to
+  return.
+- **`toggleSection()` JS helper removed** — no toggles remain on
+  the page after the welcome-blob deletion.
+
+### Fixed (PHP 8.2 deprecation)
+- `${size}px` → `{$size}px` in the dashboard list-table render.
+  `${var}` string interpolation is deprecated in PHP 8.2 and will
+  hard-error in PHP 9.
+
+### Notes
+- The dedicated **About** page (`Settings → WP Notes → About WP
+  Notes`) is unchanged and still renders `wp_notes_about_page()` from
+  `inc/wp-notes-about.php`. All the long welcome/about copy lives
+  there — exactly where it belongs.
+- Banner image still renders, in its own bordered container at the
+  top of the page. Moved out of the deleted nested toggle so it
+  actually shows.
+- Storage model is unchanged — notes still live in `wp_options`
+  under `wp_notes` / `wp_done_notes`. The UX cleanup is purely
+  presentational.
+
 ### Fixed
 - **"Add New Note" sidebar submenu opening the WordPress post editor.**
   The plugin registered a `wp_note` custom post type with