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/pages/admin/bots/[bot_id]/(partials)/message-attachment.tsx

@@ -0,0 +1,40 @@
+import Img from "@moduletrace/twui/layout/Img";
+import Link from "@moduletrace/twui/layout/Link";
+import Span from "@moduletrace/twui/layout/Span";
+import type { BotMessageAttachment } from "@/src/types";
+import AttachmentIcon from "./attachment-icon";
+
+/**
+ * One file on a message: an image as a thumbnail, anything else as a
+ * named chip. Both open the file in a new tab.
+ */
+export default function MessageAttachment({
+    name,
+    media_type,
+    url,
+    thumbnail_url,
+}: BotMessageAttachment) {
+    if (media_type == "image") {
+        return (
+            <Link href={url} target="_blank" title={name} className="block">
+                <Img
+                    src={thumbnail_url || url}
+                    alt={name}
+                    className="max-h-48 max-w-64 rounded-default-lg border border-solid border-hairline object-cover"
+                />
+            </Link>
+        );
+    }
+
+    return (
+        <Link
+            href={url}
+            target="_blank"
+            title={name}
+            className="flex max-w-64 items-center gap-2 rounded-default-lg border border-solid border-hairline bg-surface px-3 py-2 text-[13px] leading-[18px] text-ink no-underline hover:border-hairline-strong"
+        >
+            <AttachmentIcon media_type={media_type} />
+            <Span className="truncate">{name}</Span>
+        </Link>
+    );
+}