stage-9: heartbeat system with periodic checks

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/adapters/discord_bot.py

@@ -123,6 +123,7 @@ def create_bot(config: Config) -> discord.Client:
             "`/model <choice>` — Change model for this channel's session",
             "`/logs [n]` — Show last N log lines (default 10)",
             "`/restart` — Restart the bot process (owner only)",
+            "`/heartbeat` — Run heartbeat health checks",
             "",
             "**Cron Jobs**",
             "`/cron list` — List all scheduled jobs",
@@ -400,6 +401,18 @@ def create_bot(config: Config) -> discord.Client:
 
     tree.add_command(cron_group)
 
+    @tree.command(name="heartbeat", description="Run heartbeat health checks")
+    async def heartbeat_cmd(interaction: discord.Interaction) -> None:
+        from src.heartbeat import run_heartbeat
+        await interaction.response.defer(ephemeral=True)
+        try:
+            result = await asyncio.to_thread(run_heartbeat)
+            await interaction.followup.send(result, ephemeral=True)
+        except Exception as e:
+            await interaction.followup.send(
+                f"Heartbeat error: {e}", ephemeral=True
+            )
+
     @tree.command(name="channels", description="List registered channels")
     async def channels(interaction: discord.Interaction) -> None:
         ch_map = config.get("channels", {})