Update README and add workspace file

- Enhance README with project details and local development instructions
- Add VS Code workspace file for improved project management
- Update Hugo Coder theme submodule

ericxliu-me.code-workspace

@@ -0,0 +1,7 @@
+{
+	"folders": [
+		{
+			"path": "."
+		}
+	]
+}