Add a live status line to the stats panel

Shows what's happening right now underneath the table (connecting,
resolving the friend, discovering targets, fetching channel history,
waiting out a jittered delay before reacting, sending a reaction,
removing a reaction during --undo, etc). Status updates are cheap
and DB-free, using the last fetched stats for re-rendering.

bot/undo.py

@@ -24,6 +24,9 @@ async def undo_all_reactions(client: discord.Client, storage: Storage, display:
         emoji = row["emoji"]
         should_clear_log = True
 
+        if display is not None:
+            display.set_status(f"Removing reaction from message {message_id} ({i}/{total})...")
+
         try:
             channel = client.get_channel(channel_id) or await client.fetch_channel(channel_id)
             message = await channel.fetch_message(message_id)
@@ -41,11 +44,17 @@ async def undo_all_reactions(client: discord.Client, storage: Storage, display:
             if display is not None:
                 await display.refresh()
 
-        await asyncio.sleep(human_jitter())
+        delay = human_jitter()
+        if display is not None:
+            display.set_status(f"Waiting {delay:.1f}s before next removal...")
+        await asyncio.sleep(delay)
 
+    if display is not None:
+        display.set_status("Clearing channel resume points and found-message log...")
     cleared = await asyncio.to_thread(storage.clear_scan_state)
     await asyncio.to_thread(storage.reset_message_counts)
     if display is not None:
+        display.set_status("Undo complete.")
         await display.refresh()
     log.info(
         "Undo complete: removed %d/%d reaction(s), cleared %d channel resume point(s) — "