Add the harness, envs, per-bot models and chat attachments

- Harness: providers, model catalog synced hourly, automatic free picks,
  cooldowns, tool loop with context trimming, MCP computer tools
- Bots queue runs replies and tasks through the harness; jobs wait
  (attempt refunded) while every model is resting
- Envs: Settings > Environment, scoped general/workspace/computer,
  written to computers and redacted from tool output
- Models: Settings > Models, per-harness provider select defaulting to
  OpenRouter, and a models modal on each bot's chat (the coordinator's
  edits the defaults)
- Chat: thinking row while a reply runs, file attachments (upload,
  paste, drop) that replies read as images, audio and document text
- Fix media uploads failing after a user's first file, and private
  files being served from the public media path

Co-Authored-By: Claude Opus 5.5 <[email protected]>

src/bots-queue/types.ts

@@ -29,6 +29,10 @@ export type BotJobOutcome = {
      */
     result: string;
     needs_you?: boolean;
+    /**
+     * Finish without posting `result` (a reply with nothing left to answer).
+     */
+    silent?: boolean;
 };
 
 export type BotJobRunner = (context: BotJobContext) => Promise<BotJobOutcome>;