feat: lightweight bootstrap context mode for heartbeat/cron runs (openclaw#26064) thanks @jose-velez

Verified:
- pnpm build
- pnpm check (fails on pre-existing unrelated repo issues in extensions/diffs and src/agents/tools/nodes-tool.test.ts)
- pnpm vitest run src/agents/bootstrap-files.test.ts src/infra/heartbeat-runner.model-override.test.ts src/cli/cron-cli.test.ts
- pnpm test:macmini (fails on pre-existing extensions/diffs import errors; touched suites pass)

Co-authored-by: jose-velez <10926182+jose-velez@users.noreply.github.com>
Co-authored-by: Tak Hoffman <781889+Takhoffman@users.noreply.github.com>

src/agents/bootstrap-files.test.ts

@@ -1,3 +1,4 @@
+import fs from "node:fs/promises";
 import path from "node:path";
 import { afterEach, beforeEach, describe, expect, it } from "vitest";
 import {
@@ -97,4 +98,32 @@ describe("resolveBootstrapContextForRun", () => {
 
     expect(extra?.content).toBe("extra");
   });
+
+  it("uses heartbeat-only bootstrap files in lightweight heartbeat mode", async () => {
+    const workspaceDir = await makeTempWorkspace("openclaw-bootstrap-");
+    await fs.writeFile(path.join(workspaceDir, "HEARTBEAT.md"), "check inbox", "utf8");
+    await fs.writeFile(path.join(workspaceDir, "SOUL.md"), "persona", "utf8");
+
+    const files = await resolveBootstrapFilesForRun({
+      workspaceDir,
+      contextMode: "lightweight",
+      runKind: "heartbeat",
+    });
+
+    expect(files.length).toBeGreaterThan(0);
+    expect(files.every((file) => file.name === "HEARTBEAT.md")).toBe(true);
+  });
+
+  it("keeps bootstrap context empty in lightweight cron mode", async () => {
+    const workspaceDir = await makeTempWorkspace("openclaw-bootstrap-");
+    await fs.writeFile(path.join(workspaceDir, "HEARTBEAT.md"), "check inbox", "utf8");
+
+    const files = await resolveBootstrapFilesForRun({
+      workspaceDir,
+      contextMode: "lightweight",
+      runKind: "cron",
+    });
+
+    expect(files).toEqual([]);
+  });
 });