Add --raw flag to csv command to skip aggregation

- Add `to_csv_entries()` to output.py: converts raw rows to write_csv
  entries one-for-one, without merging by (project, description)
- Add `--raw` flag to the csv subparser; _cmd_csv branches on it
- Add TestToCsvEntries with 6 tests
- Update README with --raw usage example
- Add .coverage and htmlcov/ to .gitignore

src/timesheets/cli.py

@@ -19,6 +19,7 @@ from .output import (
     print_summary_weekly,
     print_summary_weekly_short,
     print_summary_weekly_totals,
+    to_csv_entries,
     write_csv,
 )
 from .parser import (
@@ -130,6 +131,15 @@ def build_parser() -> argparse.ArgumentParser:
         help="Export timesheet entries as CSV.",
     )
     _add_shared_args(csv_parser)
+    csv_parser.add_argument(
+        "--raw",
+        action="store_true",
+        default=False,
+        help=(
+            "Skip aggregation: output one CSV row per timesheet entry instead of "
+            "combining entries that share the same project and story."
+        ),
+    )
 
     status_parser = subparsers.add_parser(
         "status",
@@ -389,15 +399,15 @@ def _cmd_csv(args: argparse.Namespace, config: dict) -> None:
     rows = _resolve_rows(args, config, target_date)
     if not rows:
         print("Warning: no timesheet rows found in input.", file=sys.stderr)
-    aggregated = aggregate_rows(rows)
+    entries = to_csv_entries(rows) if args.raw else aggregate_rows(rows)
     project_map = _resolve_project_map(args, config)
 
     if args.output:
         with open(args.output, "w", newline="", encoding="utf-8") as f:
-            write_csv(aggregated, f, date_str, project_map)
+            write_csv(entries, f, date_str, project_map)
         print(f"Written to {args.output}", file=sys.stderr)
     else:
-        write_csv(aggregated, sys.stdout, date_str, project_map)
+        write_csv(entries, sys.stdout, date_str, project_map)
 
 
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