Fix paste-to-app, settings highlight, and titleBarStyle casing

Paste fix:
- Switch from std::process::Command to tokio::process::Command to avoid
  blocking the async runtime (was stalling the paste action)
- Use explicit AppleScript that activates the frontmost app before sending
  Cmd+V keystroke, making paste more reliable
- Increase delay to 300ms for macOS app refocus
- Add tokio "process" feature

Settings highlight fix:
- SettingsPanel now uses local useState for immediate optimistic updates
  when clicking position/history buttons, instead of waiting for the
  parent prop round-trip
- Buttons highlight instantly on click, then sync with backend

Config fix:
- titleBarStyle must be PascalCase "Overlay" in Tauri 2 config (was
  lowercase "overlay" which caused a startup error)

Co-authored-by: Cursor <cursoragent@cursor.com>

src-tauri/Cargo.lock

@@ -3098,6 +3098,16 @@ version = "1.3.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "0fda2ff0d084019ba4d7c6f371c95d8fd75ce3524c3cb8fb653a3023f6323e64"
 
+[[package]]
+name = "signal-hook-registry"
+version = "1.4.8"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c4db69cba1110affc0e9f7bcd48bbf87b3f4fc7c61fc9155afd4c469eb3d6c1b"
+dependencies = [
+ "errno",
+ "libc",
+]
+
 [[package]]
 name = "simd-adler32"
 version = "0.3.9"
@@ -3742,6 +3752,7 @@ dependencies = [
  "libc",
  "mio",
  "pin-project-lite",
+ "signal-hook-registry",
  "socket2",
  "tokio-macros",
  "windows-sys 0.61.2",