feat(text): refactored text processing with UTF-16 optimization and ANSI state bitflags

- Added `visibleWidth()` function to measure visible text width while excluding ANSI codes.
- Optimized text processing from UTF-8 to UTF-16 implementation with direct JsString handling for improved performance.
- Refactored ANSI state tracking to use bitflags-based SgrState struct instead of individual boolean fields for more efficient storage.
- Introduced ColorCode enum to represent color codes (Basic, Indexed, Rgb) for better type safety.
- Added comprehensive test coverage for UTF-16 text processing, ANSI detection, and width calculations.
- Updated napi feature from 'napi8' to 'napi10' and added unicode-segmentation dependency.

packages/coding-agent/src/task/executor.ts

@@ -135,7 +135,7 @@ function resolveModelOverride(
 ): { model?: Model<Api>; thinkingLevel?: ThinkingLevel } {
 	if (modelPatterns.length === 0) return {};
 	const matchPreferences = { usageOrder: settings?.getStorage()?.getModelUsageOrder() };
-	const roles = settings?.serialize().modelRoles as Record<string, string> | undefined;
+	const roles = settings?.getGroup("modelRoles");
 	for (const pattern of modelPatterns) {
 		const normalized = pattern.trim().toLowerCase();
 		if (!normalized || DEFAULT_MODEL_ALIASES.has(normalized)) {