Initial scaffold: blob store server, CLI scripts, and PWA share target

Clipboard/screenshot sync across own devices via a single DEVICE_TOKEN-gated
blob store, plus a small installable web app so a phone can push/pull
clips and share screenshots via the OS share sheet.

cli/scrot-shot

@@ -0,0 +1,33 @@
+#!/usr/bin/env bash
+# Captures a region screenshot, pushes it to scrot as a `shot` blob, and
+# copies the returned public link to the clipboard.
+set -euo pipefail
+
+: "${SCROT_SERVER:?set SCROT_SERVER, e.g. https://scrot.example.com}"
+: "${DEVICE_TOKEN:?set DEVICE_TOKEN}"
+
+tmpfile=$(mktemp --suffix=.png)
+trap 'rm -f "$tmpfile"' EXIT
+
+if [ -n "${WAYLAND_DISPLAY:-}" ]; then
+  grim -g "$(slurp)" "$tmpfile"
+else
+  maim -s "$tmpfile"
+fi
+
+response=$(curl -sf -X POST "$SCROT_SERVER/api/blobs" \
+  -H "X-Device-Token: $DEVICE_TOKEN" \
+  -H "X-Blob-Kind: shot" \
+  -H "Content-Type: image/png" \
+  --data-binary "@$tmpfile")
+
+url=$(printf '%s' "$response" | grep -o '"url":"[^"]*"' | cut -d'"' -f4)
+full_url="$SCROT_SERVER$url"
+
+if [ -n "${WAYLAND_DISPLAY:-}" ]; then
+  printf '%s' "$full_url" | wl-copy
+else
+  printf '%s' "$full_url" | xclip -selection clipboard
+fi
+
+echo "screenshot uploaded: $full_url"