Add devcontainer setup (#4143)

Co-authored-by: Angelos Bouklis <me@arjix.dev>
Co-authored-by: JellyBrick <shlee1503@naver.com>

.devcontainer/devcontainer.json

@@ -0,0 +1,16 @@
+// For format details, see https://aka.ms/devcontainer.json. For config options, see the
+// README at: https://github.com/devcontainers/templates/tree/main/src/typescript-node
+{
+	"name": "Pear Desktop - Dev Container",
+	// Keep in sync with `.github/workflows/build.yml`
+	"image": "mcr.microsoft.com/devcontainers/typescript-node:24",
+	// Features to add to the dev container. More info: https://containers.dev/features.
+	"features": {},
+	"postCreateCommand": "pnpm install --frozen-lockfile"
+	// Use 'forwardPorts' to make a list of ports inside the container available locally.
+	// "forwardPorts": [],
+	// Configure tool-specific properties.
+	// "customizations": {},
+	// Uncomment to connect as root instead. More info: https://aka.ms/dev-containers-non-root.
+	// "remoteUser": "root"
+}