feat(coding-agent): added multi-file edits in coding-agent with per-entry payloads

- Added multi-file edit payload support by requiring per-entry `edits` arrays across patch, hashline, replace, and chunk modes.
- Changed edit schemas and validators to move `path` (and `sel`->`path`) and op data into each edit entry.
- Changed edit execution flow to parse `file:selector` paths, run single-entry executors per file, and return grouped per-file results.
- Updated chunk diff rendering and test expectations to emit consistent anchor gutters with spaced pipes and `^` head-line markers.

packages/coding-agent/test/edit-diff.test.ts

@@ -245,7 +245,7 @@ describe("computeHashlineDiff", () => {
 		await Bun.write(sourcePath, "first\n");
 
 		const result = await computeHashlineDiff(
-			{ path: sourcePath, edits: [{ loc: "append", content: "second" }] },
+			{ path: sourcePath, edits: [{ path: sourcePath, loc: "append", content: "second" }] },
 			tempDir,
 		);
 		expect("diff" in result).toBe(true);