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/harness/text/generate-text.ts

@@ -0,0 +1,96 @@
+import HarnessError from "../harness-error";
+import grabHarnessAdapter from "../providers/grab-harness-adapter";
+import resolveHarnessCandidates from "../resolve/resolve-harness-candidates";
+import withCandidates from "../resolve/with-candidates";
+import type {
+    HarnessCandidate,
+    HarnessChatResult,
+    HarnessMessage,
+    HarnessToolDefinition,
+} from "../types";
+import prepareMessagesForModel from "./prepare-messages-for-model";
+import stripThinkTags from "./strip-think-tags";
+
+export type GenerateTextParams = {
+    messages: HarnessMessage[];
+    tools?: HarnessToolDefinition[];
+    /**
+     * Resolved for the text harness when not given.
+     */
+    candidates?: HarnessCandidate[];
+    /**
+     * Tried first: the model the run already uses.
+     */
+    prefer_key?: string;
+    max_tokens?: number;
+    temperature?: number;
+    signal?: AbortSignal;
+    /**
+     * Media readings shared across calls of one run.
+     */
+    media_cache?: Map<string, string>;
+    /**
+     * The bot the turn is for: its own models are used where it has them.
+     */
+    bot_id?: number | string;
+};
+
+export type GenerateTextResult = HarnessChatResult & {
+    candidate: HarnessCandidate;
+};
+
+/**
+ * One model turn on the text harness, falling back across its models.
+ * Media the model can't take is read by the helper harnesses first.
+ * Reasoning tags are stripped from the answer.
+ */
+export default async function generateText({
+    messages,
+    tools,
+    candidates,
+    prefer_key,
+    max_tokens,
+    temperature,
+    signal = new AbortController().signal,
+    media_cache = new Map(),
+    bot_id,
+}: GenerateTextParams): Promise<GenerateTextResult> {
+    const { result, candidate } = await withCandidates({
+        harness: "text",
+        candidates:
+            candidates || (await resolveHarnessCandidates({ harness: "text", bot_id })),
+        prefer_key,
+        run: async (candidate) => {
+            const answer = await grabHarnessAdapter({
+                kind: candidate.provider.kind,
+            }).chat({
+                candidate,
+                messages: await prepareMessagesForModel({
+                    messages,
+                    model: candidate.model,
+                    cache: media_cache,
+                    signal,
+                    bot_id,
+                }),
+                tools,
+                max_tokens,
+                temperature,
+                signal,
+            });
+
+            const text = answer.text ? stripThinkTags({ text: answer.text }) : "";
+
+            if (!text && !answer.tool_calls.length) {
+                throw new HarnessError({
+                    message: `The model returned an empty answer.`,
+                    retryable: true,
+                    candidate_key: candidate.key,
+                });
+            }
+
+            return { ...answer, text: text || null };
+        },
+    });
+
+    return { ...result, candidate };
+}