feat: consolidated and automate changelog management

- Added `rewrite-changelog.ts` and `fix-changelogs.ts` utilities to automate the consolidation of release notes using LLM-assisted processing.
- Updated multiple internal changelog files by consolidating redundant entries and improving phrasing for readability.
- Implemented `previewLine` utility in `coding-agent` to prevent visual spillover in status rows by managing text truncation and whitespace.
- Updated `package.json` with new workflow scripts for managing package-level change histories and documentation indexes.

packages/coding-agent/src/tools/render-utils.ts

@@ -99,6 +99,17 @@ export function getPreviewLines(text: string, maxLines: number, maxLineLen: numb
 	return lines.slice(0, maxLines).map(l => truncateToWidth(l.trim(), maxLineLen, ellipsis));
 }
 
+/**
+ * Collapse a possibly multi-line string into a single line, then truncate it to
+ * `maxWidth` display cells. {@link truncateToWidth} alone caps width but
+ * newlines are zero-width, so multi-line content (markdown briefs, tool args,
+ * provider errors) would otherwise spill a single status row across several
+ * visual lines. Whitespace runs collapse to one space, so tabs are handled too.
+ */
+export function previewLine(text: string, maxWidth: number, ellipsis?: Ellipsis): string {
+	return truncateToWidth(text.replace(/\s+/g, " ").trim(), maxWidth, ellipsis);
+}
+
 // =============================================================================
 // URL Utilities
 // =============================================================================