fix(bridge): step structure discovery + approval watcher + AI text relay

- plannerResponse.response = user-facing text field (confirmed)
- step.runCommand.commandLine = command (not toolCall.argumentsJson)
- Add response watcher: bridge/response/ → ResolveOutstandingSteps RPC
- Fix AI text: use modifiedResponse/response, last-wins, dedup
- Fix flooding: slice(-delta) to skip old steps on reload
- Bot: 404 cache invalidation for deleted Discord channels

bot.py

@@ -579,7 +579,16 @@ class GravityBot(commands.Bot):
                                     color=discord.Color.purple(),
                                     timestamp=datetime.now(timezone.utc),
                                 )
-                                await channel.send(embed=embed)
+                                try:
+                                    await channel.send(embed=embed)
+                                except discord.NotFound:
+                                    # Channel was deleted — invalidate cache and retry once
+                                    logger.warning(f"Channel deleted for {project}, re-creating...")
+                                    self.project_channels.pop(project, None)
+                                    channel = await self._get_channel(project)
+                                    if channel:
+                                        await channel.send(embed=embed)
+                                    break
 
                     f.unlink()  # Cleanup
                 except (json.JSONDecodeError, OSError) as e: