Add Sky Catalog section to homepage introducing Craft integration

src/content/docs/index.mdx

@@ -27,7 +27,7 @@ Birdcage turns salvaged RV satellite dishes into general-purpose AZ/EL positione
 
 <CardGrid>
   <Card title="Satellite Tracking" icon="star">
-    Real-time pass prediction from the [Craft API](https://space.warehack.ing), or connect Gpredict via the built-in rotctld server. Search by name, filter by elevation, track automatically.
+    Search the sky catalog by name, track targets at 1 Hz, predict upcoming passes. Works standalone via the Craft API or with Gpredict through the built-in rotctld server.
     [Tracking guide &rarr;](/guides/satellite-tracking/)
   </Card>
   <Card title="Camera Capture" icon="seti:image">
@@ -52,6 +52,27 @@ Birdcage turns salvaged RV satellite dishes into general-purpose AZ/EL positione
   </Card>
 </CardGrid>
 
+## The Sky Catalog
+
+Birdcage doesn't maintain its own TLE files or orbital prediction engine. It talks to
+[Craft](https://space.warehack.ing) — an open API that knows where everything is.
+Search "ISS" and get its current azimuth and elevation from your location. Search "Moon"
+and point the dish at it. The catalog covers LEO satellites, GPS constellations, geostationary
+birds, deep space probes, and celestial bodies — anything with a known ephemeris.
+
+The integration runs at three levels:
+
+- **TUI Craft mode** (F2 → Craft tab) — search, select a target, hit Track. The dish follows at 1 Hz.
+  Pass predictions show rise time, peak elevation, and duration. Pass-state transitions
+  (AOS → TCA → LOS) feed the Camera overlay for automated capture.
+- **MCP server** — `search_satellites`, `get_passes`, `get_next_pass`, and `get_visible_targets`
+  tools let any MCP client query the catalog and compose tracking workflows.
+- **rotctld bridge** — Gpredict and other Hamlib-compatible controllers drive the dish via
+  the built-in TCP server on port 4533. Craft provides the orbital data; Gpredict does the math.
+
+No NORAD catalog numbers to memorize, no TLE files to download, no prediction libraries to configure.
+Type a name, get a position.
+
 ## The TUI
 
 ![Birdcage TUI — six screens shown in demo mode](/screenshots/tui-collage.png)