feat: upgrade to version 2.0.0-alpha with mainstream dependencies

- Update application version to 2.0.0-alpha
- Update application name to 'Ambient Light Control'
- Upgrade Node.js requirement to >=22.0.0 (current LTS)
- Upgrade pnpm requirement to >=10.0.0 (current stable)
- Update all GitHub Actions workflows to use Node.js 22 and pnpm 10
- Update README.md with current version requirements
- Add comprehensive project metadata to package.json
- Remove obsolete src-tauri/src-tauri directory structure
- Update Cargo.toml with proper project information

src-tauri/Cargo.toml

@@ -1,10 +1,10 @@
 [package]
-name = "test-demo"
-version = "0.0.0"
-description = "A Tauri App"
-authors = ["you"]
-license = ""
-repository = ""
+name = "ambient-light-control"
+version = "2.0.0-alpha"
+description = "A desktop application for controlling ambient lighting based on screen content"
+authors = ["Ivan Li"]
+license = "MIT"
+repository = "https://github.com/ivan/display-ambient-light"
 edition = "2021"
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html