fix: update checker — fall back to /tags when no formal Gitea Release exists (v3.3.2)

The v3.3.0 update checker only queried Gitea's /releases/latest
endpoint, which requires a formal Release object (created via the
Gitea web UI with optional notes + zip assets attached). A plain
"git tag v3.3.x && git push --tags" from the terminal does NOT
create that Release object — so the checker kept returning "No
releases tagged on the Gitea repo yet" even when tags existed.

wp_notes_fetch_latest_release() now falls back to the
/tags?limit=1 endpoint when /releases/latest returns 404 (or any
non-200). It synthesises a release-like payload from the newest
tag — tag_name, html_url pointing at the tag view, tag message as
the body, empty assets[] so the existing download-URL logic falls
through to Gitea's source-archive URL pattern (/archive/<tag>.zip).

Net effect: the "Check now" button now finds the latest version
whether David creates formal Gitea Releases OR just pushes tags
with "git push --tags". No workflow change required.

Discovered while diagnosing why "Check now" wasn't seeing today's
v3.1.0/v3.2.0/v3.3.0/v3.3.1 tags (just pushed in this session)
— the tags were there, the formal Release objects were not.

KNOWN LIMITATION (not a bug — flagged)
The Gitea repo ranger/a-wp-notes-v3 is currently private. Anonymous
API requests get a 404 (Gitea's standard behaviour for private
repos). The updater code is correct but can't actually reach the
API on a private repo without authentication. Fix: change the
repo visibility to public on Gitea — appropriate anyway for a
GPL-licensed plugin headed for the WordPress.org marketplace.

VERSION BUMP
- wp-notes.php header 3.3.1 → 3.3.2
- WP_NOTES_VERSION constant 3.3.1 → 3.3.2
- About page version-history leads with v3.3.2; v3.3.1 demoted

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

inc/wp-notes-about.php

@@ -125,7 +125,11 @@ function wp_notes_about_page() {
                 <h2>Version history</h2>
                 <ul>
                     <li>
-                        <span class="ver">v3.3.1</span> &mdash; 25 May 2026 <span class="latest">latest</span><br>
+                        <span class="ver">v3.3.2</span> &mdash; 25 May 2026 <span class="latest">latest</span><br>
+                        Update checker now falls back to Gitea's <code>/tags</code> endpoint when no formal Release object exists for the latest tag. Means a plain <code>git tag &amp;&amp; git push --tags</code> is enough to make the &ldquo;Check now&rdquo; button report a new version &mdash; no need to manually create a Release in the Gitea web UI.
+                    </li>
+                    <li>
+                        <span class="ver">v3.3.1</span> &mdash; 25 May 2026<br>
                         Dropped the <code>WP</code> prefix &mdash; the plugin is now just <strong>Logbook</strong>. Cleaner name, also clears a potential WordPress.org trademark-policy hurdle if/when the plugin ever lands on the marketplace.
                     </li>
                     <li>