fix(tui): classified underscore as word char for ctrl+w

`getWordNavKind` ran the `\p{P}` punctuation test before the `_` check, so
underscore (Unicode `Pc`) returned "delimiter" and `moveWordLeft` stopped at
each underscore. Ctrl+W deleted only the trailing segment of snake_case
identifiers. Reordered the underscore check ahead of the punctuation/symbol
test and removed the dead `ch === "_"` branch.

Fixes #4776

packages/tui/CHANGELOG.md

@@ -2,6 +2,10 @@
 
 ## [Unreleased]
 
+### Fixed
+
+- Fixed `Ctrl+W` (delete word backward) stopping at underscores in snake_case identifiers; `_` is now classified as a word character so `allowed_openai_params` deletes as a single word ([#4776](https://github.com/can1357/oh-my-pi/issues/4776)).
+
 ## [16.3.10] - 2026-07-06
 
 ### Fixed

packages/tui/src/utils.ts

@@ -394,6 +394,7 @@ export function getWordNavKind(grapheme: string): WordNavKind {
 	const ch = firstCodePointChar(grapheme);
 	if (!ch) return "other";
 	if (WORD_NAV_RE_WHITESPACE.test(ch)) return "whitespace";
+	if (ch === "_") return "word";
 	if (WORD_NAV_RE_PUNCT.test(ch) || WORD_NAV_RE_SYMBOL.test(ch)) return "delimiter";
 	if (
 		WORD_NAV_RE_HAN.test(ch) ||
@@ -403,7 +404,7 @@ export function getWordNavKind(grapheme: string): WordNavKind {
 	) {
 		return "cjk";
 	}
-	if (ch === "_" || WORD_NAV_RE_LETTER.test(ch) || WORD_NAV_RE_NUMBER.test(ch)) return "word";
+	if (WORD_NAV_RE_LETTER.test(ch) || WORD_NAV_RE_NUMBER.test(ch)) return "word";
 	return "other";
 }
 

packages/tui/test/editor.test.ts

@@ -590,6 +590,11 @@ describe("Editor component", () => {
 			editor.handleInput("\x17");
 			expect(editor.getText()).toBe("foo bar");
 
+			// snake_case identifier deletes as a single word (issue #4776)
+			editor.setText("allowed_openai_params");
+			editor.handleInput("\x17");
+			expect(editor.getText()).toBe("");
+
 			// Delete across multiple lines
 			editor.setText("line one\nline two");
 			editor.handleInput("\x17");