feat(aggregate): Support custom view mode with annotated slices

src/aggregate.py

@@ -214,6 +214,22 @@ def build_file_items(base_dir: Path, files: list[str | dict[str, Any]]) -> list[
         content = summarize.summarise_file(path, content)
       elif view_mode == "none":
        content = "(context excluded)"
+      elif view_mode == "custom":
+       if custom_slices:
+        lines = content.splitlines()
+        slices_text = []
+        for s in custom_slices:
+         start = s.get("start_line", 1)
+         end = s.get("end_line", len(lines))
+         tag = s.get("tag", "unnamed")
+         comment = s.get("comment", "")
+         s_idx = max(0, start - 1)
+         e_idx = min(len(lines), end)
+         chunk = "\n".join(lines[s_idx:e_idx])
+         slices_text.append(f"---\n[Slice: {tag}] ({comment})\nLines {start}-{end}:\n{chunk}")
+        content = "\n\n".join(slices_text)
+       else:
+        content = summarize.summarise_file(path, content)
     except FileNotFoundError:
      content = f"ERROR: file not found: {path}"
      mtime = 0.0