Add uvx install instructions and PyPI package references

Three pages updated: home, getting-started, TUI guide.
All now show uvx as the primary install method with tabbed
alternatives for pip install and from-source. Documents the
camera extra and lists all three PyPI packages.

src/content/docs/index.mdx

@@ -19,7 +19,7 @@ hero:
       variant: minimal
 ---
 
-import { Card, CardGrid, LinkCard, Aside, Steps } from '@astrojs/starlight/components';
+import { Card, CardGrid, LinkCard, Aside, Tabs, TabItem } from '@astrojs/starlight/components';
 
 Birdcage turns salvaged RV satellite dishes into general-purpose AZ/EL positioners. Point them at LEO satellites, map the RF sky, capture images during passes — the hardware doesn't care what you're tracking or why.
 
@@ -69,20 +69,20 @@ Six screens, one terminal. Everything from pass prediction to raw firmware comma
 Demo mode runs the full TUI with simulated data — every screen, every interaction. It's the fastest way to see what Birdcage can do.
 </Aside>
 
-<Steps>
-1. **Clone and install** (from the `tui/` directory):
-
-   ```bash
-   cd tui/
-   uv sync
-   ```
-
-2. **Run in demo mode:**
-
-   ```bash
-   uv run birdcage-tui --demo
-   ```
-</Steps>
+<Tabs>
+  <TabItem label="uvx (no clone needed)">
+    ```bash
+    uvx birdcage-tui --demo
+    ```
+  </TabItem>
+  <TabItem label="From source">
+    ```bash
+    cd tui/
+    uv sync
+    uv run birdcage-tui --demo
+    ```
+  </TabItem>
+</Tabs>
 
 ## Why "Birdcage"?