Upgrade TUI stack: ratatui 0.30, crossterm 0.29

Constrain run_app backend to Error = io::Error for ratatui 0.30's
associated backend error type.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

Cargo.toml

@@ -12,8 +12,8 @@ opt-level = 3
 strip = true
 
 [dependencies]
-ratatui = "0.29"
-crossterm = { version = "0.28", features = ["event-stream"] }
+ratatui = "0.30"
+crossterm = { version = "0.29", features = ["event-stream"] }
 serde = { version = "1", features = ["derive"] }
 serde_json = "1"
 dirs = "5"