Enhance TUI and core functionality: add header rendering, improve message formatting, and refine provider/model handling logic. Update dependencies.

crates/owlen-core/Cargo.toml

@@ -17,6 +17,8 @@ async-trait = "0.1"
 textwrap = { workspace = true }
 toml = { workspace = true }
 shellexpand = { workspace = true }
+regex = "1"
+once_cell = "1.21.3"
 
 [dev-dependencies]
 tokio-test = { workspace = true }