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.

tests/test_reports.py

@@ -3,10 +3,14 @@ from __future__ import annotations
 import argparse
 import json
 
+from pathlib import Path
+
 from reuse_surface.reports import (
     cohort_filters_from_args,
+    collect_gap_report,
     format_cohort_json,
     format_cohort_markdown,
+    format_gap_markdown,
     select_cohort,
 )
 
@@ -88,6 +92,38 @@ def test_format_cohort_json_payload():
     assert payload["filters"]["discovery_min"] == "D5"
 
 
+def test_collect_gap_report_from_roster():
+    root = Path(__file__).resolve().parent.parent
+    roster = root / "registry/federation/local-repo-roster.yaml"
+    report = collect_gap_report(roster)
+    assert report["summary"]["total"] == 60
+    assert len(report["publish_fail"]) == 13
+    assert report["empty_scaffold_count"] >= 40
+
+
+def test_format_gap_markdown_lists_publish_fail():
+    report = {
+        "roster_path": "/tmp/roster.yaml",
+        "summary": {"total": 60, "established": 60, "publish_pass": 47},
+        "publish_fail": [{"slug": "hub-core", "publish_note": "missing repo"}],
+        "empty_scaffold_count": 1,
+        "empty_scaffolds": ["ops-bridge"],
+        "seeded_repos": [],
+        "dedup_pending_local_owners": [],
+        "local_capability_count": 3,
+    }
+    text = format_gap_markdown(report)
+    assert "hub-core" in text
+    assert "ops-bridge" in text
+
+
+def test_cmd_report_gaps_json(monkeypatch):
+    from reuse_surface.cli import main
+
+    exit_code = main(["report", "gaps", "--format", "json"])
+    assert exit_code == 0
+
+
 def test_cmd_report_cohorts_markdown(monkeypatch):
     from reuse_surface.cli import main