feat(coder): add flow-artifacts write helper and boocontext MCP template

apps/coder/src/services/flow-artifacts.ts

@@ -0,0 +1,23 @@
+import { mkdir, writeFile } from 'node:fs/promises';
+import { join } from 'node:path';
+import { existsSync } from 'node:fs';
+
+const ARTIFACTS_ROOT = 'data/flow-artifacts';
+
+export function getArtifactPath(flowRunId: string, stepId: string): string {
+  return join(ARTIFACTS_ROOT, flowRunId, `${stepId}.md`);
+}
+
+export async function writeFlowArtifact(
+  flowRunId: string,
+  stepId: string,
+  content: string,
+): Promise<string> {
+  const dir = join(ARTIFACTS_ROOT, flowRunId);
+  if (!existsSync(dir)) {
+    await mkdir(dir, { recursive: true });
+  }
+  const path = getArtifactPath(flowRunId, stepId);
+  await writeFile(path, content, 'utf8');
+  return path;
+}