fix(rtk/find): detect and group Windows backslash-style find output (#2448)

isPathLike rejected any line with a colon, so Windows absolute paths
(C:\Users\me\a.js) were never recognized and find dumps went uncompacted.
find.js also split only on "/", mis-grouping backslash paths.

- autodetect: treat drive-letter prefix (X:\ or X:/) as path-like before
  the general colon rejection.
- find.js: split on the last "/" or "\" separator and normalize emitted
  directory labels to forward slashes.

Co-authored-by: Cursor <cursoragent@cursor.com>

tests/unit/rtkFindWindows.test.js

@@ -0,0 +1,62 @@
+// Tests for Windows path support in the `find` filter + autodetect
+// Windows absolute paths ("C:\Users\me\src\a.js") carry a drive-letter
+// separator that the Unix-only colon check used to reject, so no compaction
+// happened for Windows `find`-style dumps. See fix(rtk/find).
+import { describe, it, expect } from "vitest";
+import { autoDetectFilter } from "../../open-sse/rtk/autodetect.js";
+import { find } from "../../open-sse/rtk/filters/find.js";
+import { grep } from "../../open-sse/rtk/filters/grep.js";
+
+const WIN_PATHS = [
+  "C:\\Users\\me\\project\\src\\a.js",
+  "C:\\Users\\me\\project\\src\\b.js",
+  "C:\\Users\\me\\project\\src\\c.js"
+].join("\n");
+
+const UNIX_PATHS = [
+  "./src/a.js",
+  "./src/b.js",
+  "./src/c.js"
+].join("\n");
+
+describe("Windows find-path detection", () => {
+  it("detects Windows drive-letter paths as `find`", () => {
+    expect(autoDetectFilter(WIN_PATHS)).toBe(find);
+  });
+
+  it("still detects Unix paths as `find` (no regression)", () => {
+    expect(autoDetectFilter(UNIX_PATHS)).toBe(find);
+  });
+
+  it("still routes a Windows file:line dump to a compacting filter", () => {
+    const input = [
+      "C:\\Users\\me\\project\\src\\a.js:10:const x = 1",
+      "C:\\Users\\me\\project\\src\\b.js:20:const y = 2",
+      "C:\\Users\\me\\project\\src\\c.js:30:const z = 3"
+    ].join("\n");
+    // Each line is grep-shaped (file:line:content), so it routes to `grep`
+    // — but a drive-letter-only dump would route to `find`. Both are
+    // compaction-positive, so either is acceptable here.
+    const f = autoDetectFilter(input);
+    expect(f).not.toBeNull();
+    expect([find, grep]).toContain(f);
+  });
+});
+
+describe("Windows find-path grouping", () => {
+  it("groups Windows backslash paths and normalizes to forward slashes", () => {
+    const out = find(WIN_PATHS);
+    expect(out).toContain("3 files in 1 dirs");
+    expect(out).toContain("C:/Users/me/project/src/");
+    expect(out).toContain("a.js");
+    expect(out).toContain("b.js");
+    expect(out).toContain("c.js");
+    // backslashes must not leak into output
+    expect(out).not.toContain("\\");
+  });
+
+  it("compresses the dump (output shorter than input)", () => {
+    const out = find(WIN_PATHS);
+    expect(out.length).toBeLessThan(WIN_PATHS.length);
+  });
+});