Add SEO and GEO

README.md

@@ -15,6 +15,7 @@ The server listens on `http://localhost:8080` by default.
 - `PORT`: HTTP port, default `8080`
 - `HOST`: bind address, default `0.0.0.0`
 - `DATA_DIR`: disk storage root, default `./data`
+- `SITE_URL`: public canonical site URL used for SEO metadata, sitemaps, feeds, and `llms.txt`
 - `SEED_DEMO_MEMES`: set to `false` to disable generated demo memes on first boot
 - `ADMIN_TOKEN`: secret review URL token. If omitted, one is generated at boot and printed in server logs.
 - `OPENAI_API_KEY`: enables AI upload moderation. Without it, uploads are queued for admin review.
@@ -33,6 +34,19 @@ data/
   meta/YYYY/MM/DD/aa/bb/<sha256>.json
 ```
 
+## Discovery Metadata
+
+The app serves crawler and answer-engine metadata without adding visible page copy:
+
+- `/robots.txt`
+- `/sitemap.xml` with approved meme image entries
+- `/feed.json`
+- `/llms.txt`
+- `/site.webmanifest`
+- Open Graph, Twitter card, canonical, and JSON-LD metadata on `/`
+
+Set `SITE_URL` in production so canonical URLs use the public domain instead of an internal proxy hostname.
+
 ## Docker
 
 ```sh