[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__/heartbeat-list.test.ts

@@ -88,4 +88,105 @@ describeEmbeddedPostgres("heartbeat list", () => {
       }
     }
   });
+
+  it("returns small result json payloads unchanged from getRun", async () => {
+    const companyId = randomUUID();
+    const agentId = randomUUID();
+    const runId = randomUUID();
+
+    await db.insert(companies).values({
+      id: companyId,
+      name: "Paperclip",
+      issuePrefix: `T${companyId.replace(/-/g, "").slice(0, 6).toUpperCase()}`,
+      requireBoardApprovalForNewAgents: false,
+    });
+
+    await db.insert(agents).values({
+      id: agentId,
+      companyId,
+      name: "CodexCoder",
+      role: "engineer",
+      status: "running",
+      adapterType: "codex_local",
+      adapterConfig: {},
+      runtimeConfig: {},
+      permissions: {},
+    });
+
+    await db.insert(heartbeatRuns).values({
+      id: runId,
+      companyId,
+      agentId,
+      invocationSource: "assignment",
+      status: "succeeded",
+      resultJson: {
+        summary: "done",
+        structured: { ok: true },
+      },
+    });
+
+    const run = await heartbeatService(db).getRun(runId);
+
+    expect(run?.resultJson).toEqual({
+      summary: "done",
+      structured: { ok: true },
+    });
+  });
+
+  it("bounds oversized legacy result json payloads on getRun", async () => {
+    const companyId = randomUUID();
+    const agentId = randomUUID();
+    const runId = randomUUID();
+    const oversizedStdout = Array.from({ length: 8_000 }, (_, index) =>
+      `${index.toString(16).padStart(4, "0")}-${randomUUID()}`,
+    ).join("|");
+    const oversizedNestedPayload = Array.from({ length: 6_000 }, (_, index) =>
+      `${index.toString(16).padStart(4, "0")}:${randomUUID()}`,
+    ).join("|");
+
+    await db.insert(companies).values({
+      id: companyId,
+      name: "Paperclip",
+      issuePrefix: `T${companyId.replace(/-/g, "").slice(0, 6).toUpperCase()}`,
+      requireBoardApprovalForNewAgents: false,
+    });
+
+    await db.insert(agents).values({
+      id: agentId,
+      companyId,
+      name: "CodexCoder",
+      role: "engineer",
+      status: "running",
+      adapterType: "codex_local",
+      adapterConfig: {},
+      runtimeConfig: {},
+      permissions: {},
+    });
+
+    await db.insert(heartbeatRuns).values({
+      id: runId,
+      companyId,
+      agentId,
+      invocationSource: "assignment",
+      status: "succeeded",
+      resultJson: {
+        summary: "completed",
+        stdout: oversizedStdout,
+        nestedHuge: { payload: oversizedNestedPayload },
+      },
+    });
+
+    const run = await heartbeatService(db).getRun(runId);
+    const result = run?.resultJson as Record<string, unknown> | null;
+
+    expect(result).toMatchObject({
+      summary: "completed",
+      truncated: true,
+      truncationReason: "oversized_result_json",
+      stdoutTruncated: true,
+    });
+    expect(typeof result?.stdout).toBe("string");
+    expect((result?.stdout as string).length).toBeLessThan(oversizedStdout.length);
+    expect(result).not.toHaveProperty("nestedHuge");
+  });
 });