feat: add unicode-aware soft-wrap modes and wrapped rendering (#8)

* feat(textarea): add unicode-aware soft-wrap modes and wrapped rendering

- add WrapMode API/state: None, Word, Glyph, WordOrGlyph
- keep None behavior unchanged (horizontal scroll)
- implement wrapped render path with logical-to-visual row mapping
- add Unicode-aware wrapping via unicode-segmentation + unicode-width
- make wrap width tab-aware to prevent hidden text
- apply cursor-line style on wrapped continuation rows
- fix selection at soft-wrap boundaries (no synthetic highlighted space)
- add wrap-focused tests for long text, newlines, tabs, tiny widths, and line-number
    continuations

* chore(release): bump to v0.9.0 and update README/CHANGELOG

src/highlight.rs

@@ -138,6 +138,10 @@ impl<'a> LineHighlighter<'a> {
             .push(Span::styled(format!("{}{} ", pad, row + 1), style));
     }
 
+    pub fn line_number_placeholder(&mut self, lnum_len: u8, style: Style) {
+        self.spans.push(Span::styled(spaces(lnum_len + 2), style));
+    }
+
     pub fn cursor_line(&mut self, cursor_col: usize, style: Style) {
         if let Some((start, c)) = self.line.char_indices().nth(cursor_col) {
             self.boundaries
@@ -149,6 +153,10 @@ impl<'a> LineHighlighter<'a> {
         self.style_begin = style;
     }
 
+    pub fn set_line_style(&mut self, style: Style) {
+        self.style_begin = style;
+    }
+
     #[cfg(feature = "search")]
     pub fn search(&mut self, matches: impl Iterator<Item = (usize, usize)>, style: Style) {
         for (start, end) in matches {
@@ -208,6 +216,17 @@ impl<'a> LineHighlighter<'a> {
         );
     }
 
+    pub fn selection_segment(&mut self, start_off: usize, end_off: usize, select_at_end: bool) {
+        if start_off < end_off {
+            self.boundaries
+                .push((Boundary::Select(self.select_style), start_off));
+            self.boundaries.push((Boundary::End, end_off));
+        }
+        if select_at_end {
+            self.select_at_end = true;
+        }
+    }
+
     pub fn custom(
         &mut self,
         current_row: usize,