Fix edit diff line number alignment and whitespace preservation

- Fix line numbers showing incorrect values for edits far from file start
  (e.g., 1,2,3 instead of 336,337,338). Skip count was added after displaying
  lines instead of before.

- Rewrite splitIntoTokensWithAnsi in pi-tui to preserve whitespace as separate
  tokens instead of discarding it. Wrapped lines now maintain proper alignment
  and code indentation.

- Update mom README: rename title, remove em-dashes for cleaner prose

packages/coding-agent/CHANGELOG.md

@@ -2,6 +2,12 @@
 
 ## [Unreleased]
 
+### Fixed
+
+- **Edit Diff Line Number Alignment**: Fixed two issues with diff display in the edit tool:
+  1. Line numbers were incorrect for edits far from the start of a file (e.g., showing 1, 2, 3 instead of 336, 337, 338). The skip count for context lines was being added after displaying lines instead of before.
+  2. When diff lines wrapped due to terminal width, the line number prefix lost its leading space alignment, and code indentation (spaces/tabs after line numbers) was lost. Rewrote `splitIntoTokensWithAnsi` in `pi-tui` to preserve whitespace as separate tokens instead of discarding it, so wrapped lines maintain proper alignment and indentation.
+
 ## [0.10.0] - 2025-11-27
 
 ### Added

packages/coding-agent/src/tools/edit.ts

@@ -82,6 +82,9 @@ function generateDiffString(oldContent: string, newContent: string, contextLines
 				// Add ellipsis if we skipped lines at start
 				if (skipStart > 0) {
 					output.push(` ${"".padStart(lineNumWidth, " ")} ...`);
+					// Update line numbers for the skipped leading context
+					oldLineNum += skipStart;
+					newLineNum += skipStart;
 				}
 
 				for (const line of linesToShow) {
@@ -94,11 +97,10 @@ function generateDiffString(oldContent: string, newContent: string, contextLines
 				// Add ellipsis if we skipped lines at end
 				if (skipEnd > 0) {
 					output.push(` ${"".padStart(lineNumWidth, " ")} ...`);
+					// Update line numbers for the skipped trailing context
+					oldLineNum += skipEnd;
+					newLineNum += skipEnd;
 				}
-
-				// Update line numbers for skipped lines
-				oldLineNum += skipStart + skipEnd;
-				newLineNum += skipStart + skipEnd;
 			} else {
 				// Skip these context lines entirely
 				oldLineNum += raw.length;