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/compose-job-brief.ts

@@ -0,0 +1,29 @@
+type Params = {
+    title?: string | null;
+    instructions?: string | null;
+    params?: Record<string, unknown>;
+};
+
+/**
+ * The message a bot gets to start a queued job (markdown): the brief it
+ * wrote for itself, its parameters, and how to finish.
+ */
+export default function composeJobBrief({ title, instructions, params }: Params) {
+    const parts = [`# Job: ${title?.trim() || "Untitled"}`];
+
+    if (instructions?.trim()) {
+        parts.push(instructions.trim());
+    }
+
+    if (params && Object.keys(params).length) {
+        parts.push(
+            `## Parameters\n\n\`\`\`json\n${JSON.stringify(params, null, 2)}\n\`\`\``,
+        );
+    }
+
+    parts.push(
+        `Work on this until it's done. Then reply to the user with the result: what you did, and anything they need to know or do.`,
+    );
+
+    return parts.join("\n\n");
+}