Feat: AI images on ai.direct-img.link, and as the fallback when a search finds nothing

ai.direct-img.link serves images from the AuroraIMG-6M API on our Dokploy
server (github.com/direct-img/AuroraIMG-6M) instead of searching. It takes
?src= (auroraimg-6m, case-insensitive, the default and only source for now)
and ?i=, where each i gets its own seed derived from the query, so it's a
different image of the same prompt. It has its own daily limit
(AI_DAILY_LIMIT) and AI: cache keys / ai/ R2 prefix. Failed generations
aren't cached, since they're likely temporary.

On direct-img.link and free.direct-img.link, a search that finds nothing (or
fewer than i working images) now serves an AI image of the query instead of
bad.webp. It's kept for 24h like failures were, so a later search can still
find a real image; bad.webp is only served if the AI image fails too. Its ttl
is stored in KV and R2 metadata so cache hits and deduped waiters send a
matching max-age.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

index.html

@@ -91,6 +91,24 @@ Use images to complement your responses, powered by Brave.</code></pre>
             <p style="font-size:0.85rem;color:var(--text-muted);">* Both params are optional and work in any order. Licenses come from each source and can be wrong, so check the original before publishing. Images from <a href="https://openverse.org">Openverse</a> (made using the Openverse API, not endorsed or certified by Openverse) and <a href="https://commons.wikimedia.org">Wikimedia Commons</a>.</p>
         </section>
 
+        <section>
+            <h2>AI Images</h2>
+            <p><code>ai.direct-img.link</code> generates an image of anything instead of searching, so it never comes up empty. Expect soft, painterly, abstract results: the right colors and mood, not always the exact thing.</p>
+            <pre><code>![frog wizard](https://ai.direct-img.link/frog+wizard)
+![frog wizard](https://ai.direct-img.link/frog+wizard?i=2)
+![frog wizard](https://ai.direct-img.link/frog+wizard?src=auroraimg-6m&amp;i=2)</code></pre>
+            <table>
+                <thead>
+                    <tr><th>Param</th><th>Values</th><th>Default</th></tr>
+                </thead>
+                <tbody>
+                    <tr><td><code>src</code></td><td><code>auroraimg-6m</code></td><td><code>auroraimg-6m</code></td></tr>
+                    <tr><td><code>i</code></td><td><code>1</code>–<code>20</code> (a different image each)</td><td><code>1</code></td></tr>
+                </tbody>
+            </table>
+            <p style="font-size:0.85rem;color:var(--text-muted);">* The same query always gives the same image. When a search on direct-img.link or free.direct-img.link finds nothing, an AI image is served instead. Made with <a href="https://github.com/direct-img/AuroraIMG-6M">AuroraIMG-6M</a>.</p>
+        </section>
+
         <section>
             <h2>Rate Limits</h2>
             <table>
@@ -101,9 +119,10 @@ Use images to complement your responses, powered by Brave.</code></pre>
                     <tr><td>Burst</td><td>~10 req/10s per IP</td><td>HTTP 429 (~10s)</td></tr>
                     <tr><td>New Searches</td><td><span data-limit="DAILY_LIMIT">35</span> per day per IP</td><td>Limit image served</td></tr>
                     <tr><td>New Free Searches</td><td><span data-limit="FREE_DAILY_LIMIT">100</span> per day per IP</td><td>Limit image served</td></tr>
+                    <tr><td>New AI Images</td><td><span data-limit="AI_DAILY_LIMIT">100</span> per day per IP</td><td>Limit image served</td></tr>
                 </tbody>
             </table>
-            <p style="font-size:0.85rem;color:var(--text-muted);">* free.direct-img.link has its own daily limit, separate from the main site's. Cached images don't count toward it and keep loading after you hit it. The burst limit applies to all image requests and is enforced approximately. The daily limit resets at 00:00 UTC.</p>
+            <p style="font-size:0.85rem;color:var(--text-muted);">* free.direct-img.link and ai.direct-img.link each have their own daily limit, separate from the main site's. Cached images don't count toward it and keep loading after you hit it. The burst limit applies to all image requests and is enforced approximately. The daily limit resets at 00:00 UTC.</p>
         </section>
 
         <section>