feat: set lines measure cache (#16)

* feat(textarea): add bulk replace API and transparent measure() caching

- add TextArea::set_lines(lines, cursor) for direct whole-buffer replacement
- preserve widget configuration while resetting history, selection, highlights, viewport scroll, and cached measurement state
- cache measure(width_cols) results by outer width and reuse them until dependencies change
- invalidate cached measurement on content edits, undo/redo, and measure-affecting setters
- add focused tests for set_lines behavior and cache correctness

* chore(release): bump to v0.10.2 and refresh docs

- prepare the v0.10.2 release with updated crate version and changelog entry
- refresh README coverage for fork-added APIs including wrapping, measurement, bulk replace, and custom highlights

Cargo.toml

@@ -3,7 +3,7 @@ name = "tui-textarea-2"
 homepage = "https://github.com/srothgan/tui-textarea#readme"
 repository = "https://github.com/srothgan/tui-textarea"
 documentation = "https://docs.rs/tui-textarea-2/latest/tui_textarea/"
-version = "0.10.1"
+version = "0.10.2"
 edition = "2024"
 rust-version = "1.85.0" # for Rust 2024 edition support
 authors = ["Simon Peter Rothgang <simonrothgang@icloud.com>", "rhysd <lin90162@yahoo.co.jp>"]