REUSE-WP-0015: dedup owner entries, add report gaps (T02/T03/T05)

Remove 17 owner-migrated capabilities from reuse-surface index (keep
activity-core stub). Add report gaps CLI, roster stats + gaps CI steps.
T01 remains operator-blocked on Gitea publish.

reuse_surface/cli.py

@@ -22,8 +22,12 @@ from reuse_surface.hub_sync import (
 from reuse_surface.overlaps import find_overlaps
 from reuse_surface.reports import (
     cohort_filters_from_args,
+    collect_gap_report,
+    default_roster_path,
     format_cohort_json,
     format_cohort_markdown,
+    format_gap_json,
+    format_gap_markdown,
     select_cohort,
 )
 from reuse_surface.establish import (
@@ -520,6 +524,19 @@ def cmd_report_cohorts(args: argparse.Namespace) -> int:
     return 0
 
 
+def cmd_report_gaps(args: argparse.Namespace) -> int:
+    roster_path = Path(args.roster).resolve() if args.roster else default_roster_path()
+    if not roster_path.exists():
+        print(f"error: roster not found: {roster_path}", file=sys.stderr)
+        return 1
+    report = collect_gap_report(roster_path)
+    if args.format == "json":
+        print(format_gap_json(report))
+    else:
+        print(format_gap_markdown(report), end="")
+    return 0
+
+
 def cmd_export(args: argparse.Namespace) -> int:
     index = load_index()
     bundle: dict[str, Any] = {
@@ -724,6 +741,21 @@ def main(argv: list[str] | None = None) -> int:
     )
     cohorts.set_defaults(func=cmd_report_cohorts)
 
+    gaps = report_sub.add_parser(
+        "gaps",
+        help="roster publish blockers, empty scaffolds, and dedup stubs",
+    )
+    gaps.add_argument(
+        "--roster",
+        help="workstation roster YAML (default: registry/federation/local-repo-roster.yaml)",
+    )
+    gaps.add_argument(
+        "--format",
+        choices=["markdown", "json"],
+        default="markdown",
+    )
+    gaps.set_defaults(func=cmd_report_gaps)
+
     stats = subparsers.add_parser("stats", help="registry maturity and federation stats")
     stats.add_argument("--path", help="repo root (default: cwd)")
     stats.add_argument(