docs: create README and update project configuration

- Add comprehensive README with project overview, features, and roadmap
- Update VSCode settings with new dictionary words
- Modify language switcher, mobile header, and theme toggle components
- Adjust layout and global styles
- Add language attribute to markdown example post

.vscode/settings.json

@@ -65,6 +65,8 @@
     "blurhash",
     "bmoji",
     "Frontmatter",
+    "Fuwriu",
+    "GSAP",
     "gtag",
     "Heti",
     "katex",