[codex] harden heartbeat run summaries and recovery context (#3742)

## Thinking Path

> - Paperclip orchestrates AI agents for zero-human companies
> - Heartbeat runs are the control-plane record of what agents did, why
they woke up, and what operators should see next
> - Run lists, stranded issue comments, and live log polling all depend
on compact but accurate heartbeat summaries
> - The current branch had a focused backend slice that improves how run
result JSON is summarized, how stale process recovery comments are
written, and how live log polling resolves the active run
> - This pull request isolates that heartbeat/runtime reliability work
from the unrelated UI and dev-tooling changes
> - The benefit is more reliable issue context and cheaper run lookups
without dragging unrelated board UI changes into the same review

## What Changed

- Include the latest run failure in stranded issue comments during
orphaned process recovery.
- Bound heartbeat `result_json` payloads for list responses while
preserving the raw stored payloads.
- Narrow heartbeat log endpoint lookups so issue polling resolves the
relevant active run with less unnecessary scanning.
- Add focused tests for heartbeat list summaries, live run polling,
orphaned process recovery, and the run context/result summary helpers.

## Verification

- `pnpm vitest run
server/src/__tests__/heartbeat-context-summary.test.ts
server/src/__tests__/heartbeat-list.test.ts
server/src/__tests__/agent-live-run-routes.test.ts
server/src/__tests__/heartbeat-process-recovery.test.ts`

## Risks

- The main risk is accidentally hiding a field that some client still
expects from summarized `result_json`, or over-constraining the live log
lookup path for edge-case run routing.
- Recovery comments now surface the latest failure more aggressively, so
wording changes may affect downstream expectations if anyone parses
those comments too strictly.

## Model Used

- OpenAI Codex, GPT-5-based coding agent in the Codex CLI environment.
Exact backend model deployment ID was not exposed in-session.
Tool-assisted editing and shell execution were used.

## Checklist

- [x] I have included a thinking path that traces from project context
to this change
- [x] I have specified the model used (with version and capability
details)
- [x] I have run tests locally and they pass
- [x] I have added or updated tests where applicable
- [x] If this change affects the UI, I have included before/after
screenshots
- [x] I have updated relevant documentation to reflect my changes
- [x] I have considered and documented any risks above
- [x] I will address all Greptile and reviewer comments before
requesting merge

server/src/__tests__/agent-live-run-routes.test.ts

@@ -9,6 +9,8 @@ const mockAgentService = vi.hoisted(() => ({
 const mockHeartbeatService = vi.hoisted(() => ({
   getRunIssueSummary: vi.fn(),
   getActiveRunIssueSummaryForAgent: vi.fn(),
+  getRunLogAccess: vi.fn(),
+  readLog: vi.fn(),
 }));
 
 const mockIssueService = vi.hoisted(() => ({
@@ -100,6 +102,19 @@ describe("agent live run routes", () => {
       issueId: "issue-1",
     });
     mockHeartbeatService.getActiveRunIssueSummaryForAgent.mockResolvedValue(null);
+    mockHeartbeatService.getRunLogAccess.mockResolvedValue({
+      id: "run-1",
+      companyId: "company-1",
+      logStore: "local_file",
+      logRef: "logs/run-1.ndjson",
+    });
+    mockHeartbeatService.readLog.mockResolvedValue({
+      runId: "run-1",
+      store: "local_file",
+      logRef: "logs/run-1.ndjson",
+      content: "chunk",
+      nextOffset: 5,
+    });
   });
 
   it("returns a compact active run payload for issue polling", async () => {
@@ -163,4 +178,27 @@ describe("agent live run routes", () => {
       adapterType: "codex_local",
     });
   });
+
+  it("uses narrow run log metadata lookups for log polling", async () => {
+    const res = await request(await createApp()).get("/api/heartbeat-runs/run-1/log?offset=12&limitBytes=64");
+
+    expect(res.status, JSON.stringify(res.body)).toBe(200);
+    expect(mockHeartbeatService.getRunLogAccess).toHaveBeenCalledWith("run-1");
+    expect(mockHeartbeatService.readLog).toHaveBeenCalledWith({
+      id: "run-1",
+      companyId: "company-1",
+      logStore: "local_file",
+      logRef: "logs/run-1.ndjson",
+    }, {
+      offset: 12,
+      limitBytes: 64,
+    });
+    expect(res.body).toEqual({
+      runId: "run-1",
+      store: "local_file",
+      logRef: "logs/run-1.ndjson",
+      content: "chunk",
+      nextOffset: 5,
+    });
+  });
 });