fix(windows): use posix paths for highlights and rect_map keys

str(Path) on Windows produces backslashes, breaking highlights lookups
that compare against forward-slash paths from git output.
Switch to Path.as_posix() in git_scanner.py and render_png.py.

Author: deeplook

src/dirplot/git_scanner.py

@@ -143,17 +143,17 @@ def git_apply_diff(
             fp = path_list[0]
             if fp.split("/")[0] not in exclude:
                 to_add[fp] = new_hash
-                highlights[str(repo / fp)] = "created"
+                highlights[(repo / fp).as_posix()] = "created"
         elif status == "M" and path_list:
             fp = path_list[0]
             if fp.split("/")[0] not in exclude:
                 to_add[fp] = new_hash
-                highlights[str(repo / fp)] = "modified"
+                highlights[(repo / fp).as_posix()] = "modified"
         elif status == "D" and path_list:
             fp = path_list[0]
             if fp.split("/")[0] not in exclude:
                 to_delete.append(fp)
-                highlights[str(repo / fp)] = "deleted"
+                highlights[(repo / fp).as_posix()] = "deleted"
         elif status.startswith("R") and len(path_list) >= 2:
             old_fp, new_fp = path_list[0], path_list[1]
             if old_fp.split("/")[0] not in exclude:

src/dirplot/render_png.py

@@ -263,7 +263,7 @@ def draw_node(
 
     if not node.is_dir:
         if rect_map is not None:
-            rect_map[str(node.path)] = (x, y, w, h)
+            rect_map[node.path.as_posix()] = (x, y, w, h)
         rgba = color_map.get(node.extension, (0.5, 0.5, 0.5, 1.0))
         rgb = (int(rgba[0] * 255), int(rgba[1] * 255), int(rgba[2] * 255))
         draw.rectangle([x, y, x + w - 1, y + h - 1], fill=rgb)