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.

src/weekly_activity/cli.py

@@ -8,7 +8,13 @@ from collections.abc import Sequence
 from datetime import UTC, datetime
 from pathlib import Path
 
-from weekly_activity.aggregate import build_specs, collect_specs, format_combined
+from weekly_activity.aggregate import (
+    Collected,
+    SourceSpec,
+    build_specs,
+    collect_specs,
+    format_combined,
+)
 from weekly_activity.config import ConfigError, default_config_path, load_config
 from weekly_activity.model import last_week_window
 from weekly_activity.report import format_report
@@ -128,6 +134,42 @@ def resolve_period(args: argparse.Namespace) -> tuple[datetime, datetime]:
     return last_week_window()
 
 
+_STATUS_PREFIX = "# Generating report"
+_STATUS_ERASE = "\x1b[2K\r"
+
+
+def _report_status_active() -> bool:
+    """Transient progress lines only make sense on an interactive terminal."""
+    return sys.stdout.isatty()
+
+
+def _show_report_status(name: str) -> None:
+    """Erase-then-overwrite in place; no newline keeps updates on one row."""
+    sys.stdout.write(f"{_STATUS_ERASE}{_STATUS_PREFIX}: pulling {name} data...")
+    sys.stdout.flush()
+
+
+def _hide_report_status() -> None:
+    """Erase the status row so nothing of it survives into the final output."""
+    sys.stdout.write(_STATUS_ERASE)
+    sys.stdout.flush()
+
+
+def _collect_report_sources(
+    specs: list[SourceSpec], since: datetime, until: datetime
+) -> list[Collected]:
+    """Run collect_specs per source, showing a TTY-only progress line each."""
+    show = _report_status_active()
+    collected: list[Collected] = []
+    for spec in specs:
+        if show:
+            _show_report_status(spec.name)
+        collected.extend(collect_specs([spec], since, until))
+    if show:
+        _hide_report_status()
+    return collected
+
+
 def main() -> None:
     args = parse_args()
     command = args.command or "report"
@@ -150,7 +192,7 @@ def main() -> None:
         if not specs:
             raise SystemExit(f"error: {path} enables no sources; run `weekly-activity config`.")
         since, until = resolve_period(args)
-        collected = collect_specs(specs, since, until)
+        collected = _collect_report_sources(specs, since, until)
         print(format_combined(collected, since, until))
         return