Implement ACTIVITY-WP-0022/0023: safe sink default and gap closures

Default ISSUE_SINK_TYPE to state-hub (no silent Forgejo issues), hard-fail
prune apply without live-images protection, refresh-live-images script,
disable TaskExecutor stub by default, and document consumer/sink contracts.

tests/test_forgejo_prune_context_resolver.py

@@ -36,4 +36,43 @@ def test_shell_resolver_runs_forgejo_package_prune(tmp_path, monkeypatch) -> Non
     )
 
     assert result["kind"] == "forgejo_package_prune"
-    assert result["candidate_count"] == 2
+    assert result["candidate_count"] == 2
+
+
+def test_apply_without_live_images_file_is_rejected(tmp_path) -> None:
+    """ACTIVITY-WP-0023-T03: apply=true must not run unprotected."""
+    script = tmp_path / "forgejo-package-prune"
+    script.write_text("#!/usr/bin/env bash\necho '{}'\n", encoding="utf-8")
+    script.chmod(0o755)
+
+    try:
+        CONTEXT_RESOLVER_REGISTRY["shell"]().resolve(
+            "forgejo_package_prune",
+            None,
+            {"prune_script": str(script), "max_versions": 3, "apply": True},
+        )
+        raise AssertionError("expected RuntimeError")
+    except RuntimeError as exc:
+        assert "live_images_file" in str(exc)
+
+
+def test_apply_with_empty_live_images_file_is_rejected(tmp_path) -> None:
+    script = tmp_path / "forgejo-package-prune"
+    script.write_text("#!/usr/bin/env bash\necho '{}'\n", encoding="utf-8")
+    script.chmod(0o755)
+    empty = tmp_path / "live.txt"
+    empty.write_text("", encoding="utf-8")
+
+    try:
+        CONTEXT_RESOLVER_REGISTRY["shell"]().resolve(
+            "forgejo_package_prune",
+            None,
+            {
+                "prune_script": str(script),
+                "apply": True,
+                "live_images_file": str(empty),
+            },
+        )
+        raise AssertionError("expected RuntimeError")
+    except RuntimeError as exc:
+        assert "non-empty" in str(exc) or "empty" in str(exc)

tests/test_issue_sink.py

@@ -81,6 +81,31 @@ def test_issue_core_rest_sink_posts_task_contract(monkeypatch) -> None:
     assert "review_required" not in posts[0]["json"]
 
 
+def test_default_sink_is_state_hub_not_rest(monkeypatch) -> None:
+    """ACTIVITY-WP-0022: unset ISSUE_SINK_TYPE must not open Forgejo/rest."""
+    from activity_core import issue_sink as mod
+
+    monkeypatch.delenv("ISSUE_SINK_TYPE", raising=False)
+    sink = mod.get_issue_sink()
+    assert type(sink).__name__ == "StateHubProgressSink"
+
+
+def test_unknown_sink_type_falls_back_to_state_hub(monkeypatch) -> None:
+    from activity_core import issue_sink as mod
+
+    monkeypatch.setenv("ISSUE_SINK_TYPE", "forgejo-please")
+    sink = mod.get_issue_sink()
+    assert type(sink).__name__ == "StateHubProgressSink"
+
+
+def test_rest_sink_still_available_when_explicit(monkeypatch) -> None:
+    from activity_core import issue_sink as mod
+
+    monkeypatch.setenv("ISSUE_SINK_TYPE", "rest")
+    sink = mod.get_issue_sink()
+    assert type(sink).__name__ == "IssueCoreRestSink"
+
+
 def test_issue_core_rest_sink_requires_api_key() -> None:
     sink = IssueCoreRestSink("http://issue-core.test/", api_key="")
     with pytest.raises(RuntimeError, match="ISSUE_CORE_API_KEY"):