Refactor application

- Use contexts for large-scope states
- Use OffscreenCanvas for rendering instead of hidden canvas element

src/lib/layouts/write/WriteButton.svelte

@@ -0,0 +1,68 @@
+<script lang="ts">
+  import { Button } from '$lib/components/ui/button'
+  import { getBitmapContext } from '$lib/contexts/bitmap.svelte'
+  import { getDeviceContext } from '$lib/contexts/device.svelte'
+  import { toast } from 'svelte-sonner'
+
+  interface Props {
+    onprogress: (inPropgress: boolean) => void
+  }
+
+  const { onprogress }: Props = $props()
+
+  let inProgress = $state(false)
+
+  const deviceCtx = getDeviceContext()
+  const bitmapCtx = getBitmapContext()
+
+  let disabled = $derived(deviceCtx.device === null || bitmapCtx.rendered === null || inProgress)
+  let secondary = $derived(deviceCtx.device === null)
+
+  async function connectAndWrite() {
+    if (deviceCtx.device === null || bitmapCtx.rendered === null) return
+
+    if (!deviceCtx.device.opened) {
+      try {
+        await deviceCtx.device.open()
+      } catch (e) {
+        toast.error(`Unable to open device: ${e}`)
+        return
+      }
+    }
+
+    const buffer = new Uint8Array(5000)
+    for (let y = 0; y < 200; y++) {
+      for (let xStride = 0; xStride < 25; xStride++) {
+        let cell = 0x0
+        for (let xStroll = 0; xStroll < 8; xStroll++) {
+          const index = y * 200 + xStride * 8 + xStroll
+          cell |= bitmapCtx.rendered[index] << xStroll
+        }
+        buffer[y * 25 + xStride] = cell
+      }
+    }
+
+    inProgress = true
+
+    try {
+      await deviceCtx.device.sendReport(0, buffer)
+    } catch (e) {
+      toast.error(`Error writing to device: ${e}`)
+      return
+    } finally {
+      setTimeout(() => {
+        inProgress = false
+      }, 2000)
+    }
+
+    toast.success('Wrote pattern to device')
+  }
+
+  $effect(() => {
+    onprogress(inProgress)
+  })
+</script>
+
+<Button onclick={connectAndWrite} variant={secondary ? 'secondary' : 'default'} {disabled}>
+  Write pattern to device
+</Button>