fix(agent): bill signals scouts and all signal-report tasks to signals product

[joshsny]

Problem

LLM usage from the Signals product wasn't fully attributed to the signals gateway product. Only internal signal-report tasks routed to signals; non-internal signal-report tasks fell through to posthog_code, and headless scout runs (origin_product = signals_scout) weren't routed to signals at all.

Changes

resolveGatewayProduct now routes any signals-originated work to the signals gateway product regardless of the internal flag:

• signal_report tasks → signals (previously only when internal)
• signals_scout (headless scout runs) → signals (new)

Task["origin_product"] in @posthog/shared gains the signals_scout member to match the backend OriginProduct enum (products/tasks/backend/models.py), where the scout origin product is signals_scout.

How did you test this?

Ran the affected unit tests:
pnpm --filter @posthog/agent exec vitest run src/utils/gateway.test.ts src/server/agent-server.configure-environment.test.ts — 41 passing, including new cases for non-internal signal_report and both internal/non-internal signals_scout. Also ran tsc --noEmit on the agent package and biome on the touched files.

Automatic notifications

• Publish to changelog?
• Alert Sales and Marketing teams?

---

Created with PostHog Code from a Slack thread

[github-actions]

React Doctor found no issues in the changed files. 🎉

_{Reviewed by React Doctor for commit 023ec1f.}

[greptile-apps]

Prompt To Fix All With AI

Fix the following 1 code review issue. Work through them one at a time, proposing concise fixes.

---

### Issue 1 of 1
packages/agent/src/server/agent-server.configure-environment.test.ts:130-150
These two tests follow identical shapes — `buildServer("background").configureEnvironment({isInternal: false, originProduct: X})` → check `LLM_GATEWAY_URL` — and would be cleaner as a single `it.each`, matching the team's preference for parameterised tests. The description of the second test also says "internal or not" but only exercises `isInternal: false`; the internal path is only covered in `gateway.test.ts`.

```suggestion
  it.each([
    { originProduct: "signal_report" as const },
    { originProduct: "signals_scout" as const },
  ])(
    "tags as signals for signals-originated work (origin_product '$originProduct') regardless of internal flag",
    ({ originProduct }) => {
      buildServer("background").configureEnvironment({
        isInternal: false,
        originProduct,
      });

      expect(process.env.LLM_GATEWAY_URL).toBe(
        "https://gateway.us.posthog.com/signals",
      );
    },
  );
```

_{Reviews (1): Last reviewed commit: "fix(agent): bill signals scouts and all ..." | Re-trigger Greptile}

[greptile-apps]

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