fix(coding-agent): fixed local plan URL path separator handling in chunk edits

- Updated `chunkReadPathSeparatorIndex` to detect URL schemes and split at the final selector colon only after the URL path.
- Added tests for `parseChunkEditPath` and `parseChunkReadPath` covering local plan URLs with selectors and scheme-only URLs.

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

@@ -10,6 +10,8 @@ import {
 	DEFAULT_FUZZY_THRESHOLD,
 	findMatch,
 	loadChunkSource,
+	parseChunkEditPath,
+	parseChunkReadPath,
 } from "@oh-my-pi/pi-coding-agent/edit";
 
 describe("findMatch", () => {
@@ -217,6 +219,23 @@ describe("computeChunkDiff", () => {
 	});
 });
 
+describe("chunk path parsing", () => {
+	test("splits local plan URLs with chunk selectors after the URL path", () => {
+		expect(parseChunkEditPath("local://PLAN.md:sct_0_T#SRJJ")).toEqual({
+			filePath: "local://PLAN.md",
+			selector: "sct_0_T#SRJJ",
+		});
+		expect(parseChunkReadPath("local://PLAN.md:sct_6_R.sct_6_u#MZKS")).toEqual({
+			filePath: "local://PLAN.md",
+			selector: "sct_6_R.sct_6_u#MZKS",
+		});
+	});
+
+	test("does not treat the local URL scheme colon as a chunk selector separator", () => {
+		expect(parseChunkEditPath("local://PLAN.md")).toEqual({ filePath: "local://PLAN.md" });
+	});
+});
+
 describe("adjustIndentation", () => {
 	test("adds indentation when actualText is more indented than oldText", () => {
 		const oldText = "foo\nbar";