Drop allowlist for extra modules to install, and generalise the naming
>>> [!note] Migrated issue
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<!-- Migrated from issue #3577526. -->
Reported by: [littlepixiez](https://www.drupal.org/user/2568718)
Related to !4
>>>
<h3 id="summary-problem-motivation">Problem/Motivation</h3>
<p>When following the AI workshop at DrupalCamp England, I found it frustrating not being able to install whichever modules I wanted (for example FlowDrop UI), so manually tweaked the allowlist to let me. It would be good to just put a cap on the amount allowed, rather than restrict it.</p>
<p>The allowlist would also require extra maintenance, so let's remove it.</p>
<h3 id="summary-proposed-resolution">Proposed resolution</h3>
<ol>
<li>Remove the hardcoded allowlist entirely</li>
<li>Replace with a hard upper bound on the number of modules that can be requested in a single build</li>
<li>Rename <code>DP_AI_MODULES</code> to <code>DP_EXTRA_MODULES</code> to better reflect its purpose as a general extra-modules list rather than an AI-specific allowlist</li>
</ol>
<h3 id="summary-remaining-tasks">Remaining tasks</h3>
<ul>
<li>[x] Remove <code>ALLOWED_AI_MODULES</code> array and per-module validation loop from<br>
<code>scripts/fallback_setup.sh</code></li>
<li>[x] Add <code>readonly MAX_EXTRA_MODULES=15</code> count check (not user-overridable)</li>
<li>[x] Rename <code>DP_AI_MODULES</code> → <code>DP_EXTRA_MODULES</code> across all scripts, tests, config, and documentation</li>
</ul>
<h3 id="summary-api-changes">API changes</h3>
<p><strong>Environment Variables:</strong></p>
<ul>
<li><code>DP_AI_MODULES</code> — Removed. Replaced by <code>DP_EXTRA_MODULES</code>.</li>
<li><code>DP_EXTRA_MODULES</code> — New variable. Accepts any comma-separated list of Drupal module names (no allowlist), capped at 15 entries per build. The limit is enforced in Bash and cannot be overridden by the caller.</li>
</ul>
<h3 id="summary-data-model-changes">Data model changes</h3>
<p>None.</p>
issue