feat(binary): add full binary simulator with unsigned and two’s complement modes

- Introduce new Binary Simulator page with adjustable bit width (4–16 bits)
- Support unsigned and two’s complement representations with live conversion
- Add left/right shift operations and custom binary/denary input
- Implement accessible bulb-and-switch UI with MD3-inspired styling
- Add seven-segment display font assets for realistic number output
- Establish shared base layout, styles, and tooling for future simulators

Signed-off-by: Alexander Lyall <alex@adcm.uk>

src/pages/index.astro

@@ -0,0 +1,11 @@
+---
+import Welcome from '../components/Welcome.astro';
+import Layout from '../layouts/Layout.astro';
+
+// Welcome to Astro! Wondering what to do next? Check out the Astro documentation at https://docs.astro.build
+// Don't want to use any of this? Delete everything in this file, the `assets`, `components`, and `layouts` directories, and start fresh.
+---
+
+<Layout>
+	<Welcome />
+</Layout>