Refactor help plugin, and included metadata to all plugins

plugins/arxiv.py

@@ -320,3 +320,17 @@ def setup(bot):
 __version__ = "1.0.0"
 __author__ = "Funguy Bot"
 __description__ = "arXiv academic paper search"
+__help__ = """
+<details>
+<summary><strong>!arxiv</strong> – Search academic papers on arXiv</summary>
+<ul>
+<li><code>!arxiv &lt;query&gt;</code> – Search papers (shows abstracts)</li>
+<li><code>!arxiv list &lt;query&gt;</code> – List without abstracts</li>
+<li><code>!arxiv category &lt;category&gt;</code> – Browse recent papers by category</li>
+<li><code>!arxiv recent [category]</code> – Most recent papers (7 days)</li>
+<li><code>!arxiv random</code> – Random paper</li>
+<li><code>!arxiv &lt;id&gt;</code> – Get paper by arXiv ID (e.g., 2101.00101)</li>
+</ul>
+<p><strong>Categories:</strong> ai, ml, security, crypto, cv, nlp, math, physics, quantum, bio, software</p>
+</details>
+"""