Add arrow-key menus and report loading status

wizard: when stdin and stdout are both TTYs, menus render inline and
are driven by keys: up/down/j/k/Home/End move the bold '>' highlight,
Enter accepts, Esc/Ctrl-C/q back out of cancellable menus while Ctrl-C
on fixed menus still aborts. Rows redraw with erase+CR across the
option block only and clear before returning so prompts stay aligned.
Non-TTY stdio keeps the original numbered prompt verbatim.

report: each configured source shows a transient "# Generating
report: pulling <name> data..." line that is erased on completion,
only when stdout is a TTY; piped output remains exactly the report.

tests: cover the numbered fallback, row rendering, status suppression
and show+clear parity; reformat stray test files to satisfy ruff.

tests/test_cli.py

@@ -0,0 +1,76 @@
+"""Unit tests for the report command's loading-status presentation layer."""
+
+from __future__ import annotations
+
+import io
+import sys
+import unittest
+from datetime import datetime
+from unittest import mock
+
+from weekly_activity.aggregate import SourceSpec, collect_specs
+from weekly_activity.cli import _collect_report_sources
+from weekly_activity.model import ActivityReport, Section
+
+
+class StubSource:
+    """Deterministic stand-in satisfying the ActivitySource interface."""
+
+    def __init__(self, *, fail: bool = False) -> None:
+        self._fail = fail
+        self.name = "stub"
+
+    def collect(self, username: str, since: datetime, until: datetime) -> ActivityReport:
+        if self._fail:
+            raise RuntimeError("some query failed")
+        return ActivityReport(
+            source=username,
+            username=username,
+            since=since,
+            until=until,
+            sections=[Section(title="Patches", entries=["one commit"])],
+        )
+
+
+def spec(name: str, *, fail: bool = False) -> SourceSpec:
+    source = StubSource(fail=fail)
+    return SourceSpec(name=name, username="me", make=lambda: source)
+
+
+WINDOW = (datetime(2026, 8, 19), datetime(2026, 8, 26))
+
+
+class FakeTty(io.StringIO):
+    """Capture buffer that claims to be a terminal so status lines activate."""
+
+    def isatty(self) -> bool:
+        return True
+
+
+class ReportStatusTest(unittest.TestCase):
+    def test_status_is_silent_without_a_tty(self) -> None:
+        specs = [spec("alpha"), spec("beta")]
+        buffer = io.StringIO()
+        with mock.patch.object(sys, "stdout", buffer):
+            collected = _collect_report_sources(specs, *WINDOW)
+        self.assertEqual(buffer.getvalue(), "")
+        self.assertEqual(collected, collect_specs(specs, *WINDOW))
+
+    def test_status_names_current_source_then_clears_on_a_tty(self) -> None:
+        specs = [spec("launchpad"), spec("github/personal"), spec("broken", fail=True)]
+        buffer = FakeTty()
+        with mock.patch.object(sys, "stdout", buffer):
+            collected = _collect_report_sources(specs, *WINDOW)
+        text = buffer.getvalue()
+        self.assertIn("# Generating report: pulling launchpad data...", text)
+        self.assertIn("# Generating report: pulling github/personal data...", text)
+        self.assertNotIn("# Generating report: pulling broken data...\n", text)
+        # The final erase leaves nothing visible behind the transient status.
+        self.assertTrue(text.endswith("\x1b[2K\r"))
+        self.assertEqual(collected, collect_specs(specs, *WINDOW))
+        errors = [item.error for item in collected if item.error is not None]
+        self.assertTrue(errors and all("RuntimeError" in err for err in errors))
+
+
+if __name__ == "__main__":
+    unittest.main()