ux: rename "Create WP Note" → "My Notes" and "About WP Notes" → "About"

The "Create WP Note" submenu was misleadingly narrow — that page is
the central dashboard (create form + active list + completed list +
edit + restore). Renamed to "My Notes" to match the WP-native
"Posts → All Posts" pattern and reflect that users land there for
everything, not just creation.

"About WP Notes" → "About": the WP Notes brand is already carried by
the parent menu, so the submenu can be plain-spoken.

CHANGES
- wp-notes.php: WP Notes submenu "Create WP Note" → "My Notes"
- wp-notes.php: Tools menu shortcut "Create WP Note" → "My Notes"
  (same target page)
- wp-notes.php: WP Notes submenu "About WP Notes" → "About"
- wp-notes.php: callback docblock updated to reflect new name
- inc/wp-notes-about.php: page H1 trimmed to match the Tier-1 style
  on the main page (h1 "About" + version chip + wp-header-end hr),
  replacing the previous "Welcome to WP Notes About Page v3.0.2"
- inc/wp-notes-about.php: removed a redundant nested
  <div id="header"> with display:none that was dead markup leftover
  from an older layout

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

CHANGELOG.md

@@ -7,6 +7,23 @@ Format: [Keep a Changelog 1.1.0](https://keepachangelog.com/en/1.1.0/) — versi
 
 ## [Unreleased]
 
+### Changed — Menu labels: "Create WP Note" → "My Notes", "About WP Notes" → "About"
+- **"Create WP Note" submenu renamed to "My Notes"** (both in the WP
+  Notes parent menu and the Tools → quick-access shortcut). The page
+  is the central dashboard — create form + active list + completed
+  list + edit + restore — so "Create" was misleadingly narrow.
+  "My Notes" matches the WP-native `Posts → All Posts` pattern.
+- **"About WP Notes" submenu renamed to just "About".** The WP Notes
+  brand is already carried by the parent menu, so the submenu can be
+  plain-spoken.
+- **About page H1 trimmed** to match the Tier-1 style on the main
+  page: `<h1>About</h1>` + version chip instead of the old
+  *"Welcome to WP Notes About Page v3.0.2"* mouthful. Same
+  `wp-heading-inline` + `page-title-action` + `wp-header-end` recipe.
+- Removed a redundant nested `<div id="header">` with `display: none`
+  on the About page — it was dead markup leftover from an older
+  layout.
+
 ### Changed — Banner moved to About page (side-by-side intro)
 - **Banner image removed from the Create-Note page.** It was the
   first thing under the page title and took up significant vertical