Add usage/help section to NACC settings page (#27)

Surface how to use the plugin directly on the Settings → NACC admin page
(closes #26):

- "How to Use" section explaining the [nacc] shortcode and that the
  settings on the page are the site-wide defaults.
- Shortcode attribute table (theme, language, layout, special) mirroring
  README.md, noting attributes override the saved defaults per-instance.
- One-line description of each control (Theme / Language / Layout /
  Show Special Keytags).
- Link to the bundled nacc2/README.md for standalone (non-WordPress) usage.

Bump version to 6.0.2 and add a readme.txt changelog entry. Help copy is
mirrored from README.md / nacc2/README.md; escaping matches the existing
draw_settings() conventions (static markup + esc_url for the README link).

🐦‍⬛ Generated with Claude Code, orchestrated by Crow


Crow-Session: 065EC34B-D2C2-46A1-899B-EDFE29AEA7CD

Co-authored-by: Claude <noreply@anthropic.com>

Author: dgershman

nacc-wordpress-plugin.php

@@ -6,7 +6,7 @@
  * Install:           Drop this directory in the "wp-content/plugins/" directory and activate it. You need to specify "[NACC]" in the code section of a page or a post.
  * Contributors:      BMLTGuy, pjaudiomv, bmltenabled
  * Authors:           bmltenabled
- * Version:           6.0.1
+ * Version:           6.0.2
  * Requires PHP:      8.0
  * Requires at least: 5.3
  * License:           GPL v2 or later
@@ -464,6 +464,71 @@ public static function draw_settings(): void {
 				</table>
 				<?php submit_button(); ?>
 			</form>
+
+			<hr />
+
+			<h2>How to Use</h2>
+			<p>
+				Add the <code>[nacc]</code> shortcode to any page or post to embed the cleantime
+				calculator. The settings above are the site-wide defaults used whenever the
+				shortcode is placed without attributes.
+			</p>
+
+			<h3>Shortcode Attributes</h3>
+			<p>
+				All attributes are optional. Any attribute you set on the shortcode overrides the
+				saved default above for that instance only, so you can display the calculator
+				differently on different pages.
+			</p>
+			<table class="widefat striped" style="max-width: 40em;">
+				<thead>
+					<tr>
+						<th scope="col">Attribute</th>
+						<th scope="col">Values</th>
+						<th scope="col">Default</th>
+					</tr>
+				</thead>
+				<tbody>
+					<tr>
+						<td><code>theme</code></td>
+						<td>See the Theme dropdown above</td>
+						<td>Default (gray)</td>
+					</tr>
+					<tr>
+						<td><code>language</code></td>
+						<td>See the Language dropdown above</td>
+						<td><code>en</code></td>
+					</tr>
+					<tr>
+						<td><code>layout</code></td>
+						<td><code>linear</code>, <code>tabular</code></td>
+						<td><code>linear</code></td>
+					</tr>
+					<tr>
+						<td><code>special</code></td>
+						<td><code>1</code>, <code>0</code></td>
+						<td><code>0</code></td>
+					</tr>
+				</tbody>
+			</table>
+			<p>
+				Example:
+				<code>[nacc theme="NACC-BT" language="es" layout="tabular" special="1"]</code>
+			</p>
+
+			<h3>What Each Setting Does</h3>
+			<ul class="ul-disc">
+				<li><strong>Theme</strong> &mdash; the visual style (color scheme) of the keytags.</li>
+				<li><strong>Language</strong> &mdash; the language of the keytag labels and cleantime summary.</li>
+				<li><strong>Layout</strong> &mdash; <code>linear</code> shows tag fronts in a single row; <code>tabular</code> shows the tags side-by-side with their rear text.</li>
+				<li><strong>Show Special Keytags</strong> &mdash; whether the "specialty" long-term tags (over 2 years, e.g. the Decades tag) are displayed.</li>
+			</ul>
+
+			<p>
+				For standalone (non-WordPress) usage, see the
+				<a href="<?php echo esc_url( plugins_url( 'nacc2/README.md', __FILE__ ) ); ?>">nacc2/README.md</a>
+				documentation included with this plugin.
+			</p>
 		</div>
 		<?php
 	}

readme.txt

@@ -5,7 +5,7 @@ Plugin URI: https://wordpress.org/plugins/nacc-wordpress-plugin/
 Tags: na, cleantime calculator, nacc, recovery, addiction
 Requires PHP: 8.0
 Tested up to: 7.0
-Stable tag: 6.0.1
+Stable tag: 6.0.2
 License: GPLv2 or later
 License URI: http://www.gnu.org/licenses/gpl-2.0.html
 
@@ -30,6 +30,10 @@ That text will be replaced with this cleantime calculator.
 
 == Changelog ==
 
+= 6.0.2 =
+
+* Added a "How to Use" help section to the Settings → NACC admin page documenting the `[nacc]` shortcode, its attributes, and what each setting does.
+
 = 6.0.1 =
 
 * Added a "Lantern" theme matching the Lantern WordPress theme (warm parchment paper, deep ink navy, terracotta ember accents, Fraunces display serif for the cleantime number). Selectable from Settings → NACC → Theme.