Use waiting room Gravity placements

[jahooma]

Summary

Route Freebuff waiting room ad requests through a new waiting_room ads surface.
Gravity maps that surface to waiting-room-1 through waiting-room-4, while existing chat ad placements keep their current banner/choice behavior.

Validation

• bun run --cwd cli typecheck
• bun run --cwd web typecheck

[greptile-apps]

Greptile Summary

This PR routes the Freebuff waiting room ad requests through a new waiting_room surface, which Gravity maps to four dedicated placement IDs (waiting-room-1 through waiting-room-4), while existing chat ad placements continue using their current banner/choice logic. The change is well-scoped and flows cleanly from the CLI hook through the API layer to the Gravity provider.

Confidence Score: 5/5

Safe to merge; only one minor style suggestion remains.

All findings are P2. The single comment is a simplification of an intermediate variable in gravity.ts that doesn't affect correctness or runtime behavior.

web/src/lib/ad-providers/gravity.ts — minor simplification opportunity in the placement/variant derivation block.

Important Files Changed

Filename	Overview
web/src/lib/ad-providers/gravity.ts	Adds WAITING_ROOM_PLACEMENT_IDS and routes waiting_room surface requests to those placements; variant/placement derivation logic can be simplified by removing the intermediate requestedPlacementIds variable.
cli/src/hooks/use-gravity-ad.ts	Adds AdSurface type and surface option; correctly threads it into the fetch body and adds it to the useEffect dependency array.
web/src/app/api/v1/ads/_post.ts	Adds surfaceSchema validation and passes surface through to the ad provider; straightforward and correct.
web/src/lib/ad-providers/types.ts	Adds AdSurface type and optional surface field to FetchAdInput; clean addition.
cli/src/components/waiting-room-screen.tsx	Passes surface: 'waiting_room' to useGravityAd; minimal, correct one-liner change.

Prompt To Fix All With AI

This is a comment left during a code review.
Path: web/src/lib/ad-providers/gravity.ts
Line: 114-128

Comment:
**Simplify placement/variant derivation**

The intermediate `requestedPlacementIds` variable is checked twice with `?.length`, and the `length === 1 ? 'banner' : 'choice'` branch will never be `'banner'` because `WAITING_ROOM_PLACEMENT_IDS` always has 4 entries. Checking `input.surface` directly removes the extra variable and the duplicate guards.

```suggestion
      const variant =
        input.surface === 'waiting_room' ? 'choice' : getGravityVariant(userId)
      const filteredMessages = prepareGravityMessages(messages)

      const placementIds =
        input.surface === 'waiting_room'
          ? WAITING_ROOM_PLACEMENT_IDS
          : variant === 'choice'
            ? CHOICE_PLACEMENT_IDS
            : [BANNER_PLACEMENT_ID]
```

How can I resolve this? If you propose a fix, please make it concise.

_{Reviews (1): Last reviewed commit: "Use waiting room Gravity placements" | Re-trigger Greptile}

[greptile-apps]

Simplify placement/variant derivation

The intermediate requestedPlacementIds variable is checked twice with ?.length, and the length === 1 ? 'banner' : 'choice' branch will never be 'banner' because WAITING_ROOM_PLACEMENT_IDS always has 4 entries. Checking input.surface directly removes the extra variable and the duplicate guards.

Suggested change

	const requestedPlacementIds =
	input.surface === 'waiting_room' ? WAITING_ROOM_PLACEMENT_IDS : undefined
	const variant = requestedPlacementIds?.length
	? requestedPlacementIds.length === 1
	? 'banner'
	: 'choice'
	: getGravityVariant(userId)
	const filteredMessages = prepareGravityMessages(messages)
	const placements =
	variant === 'choice'
	? CHOICE_PLACEMENT_IDS.map((id) => ({
	placement: 'below_response',
	placement_id: id,
	}))
	: [{ placement: 'below_response', placement_id: BANNER_PLACEMENT_ID }]
	const placementIds = requestedPlacementIds?.length
	? requestedPlacementIds
	: variant === 'choice'
	? CHOICE_PLACEMENT_IDS
	: [BANNER_PLACEMENT_ID]
	const variant =
	input.surface === 'waiting_room' ? 'choice' : getGravityVariant(userId)
	const filteredMessages = prepareGravityMessages(messages)
	const placementIds =
	input.surface === 'waiting_room'
	? WAITING_ROOM_PLACEMENT_IDS
	: variant === 'choice'
	? CHOICE_PLACEMENT_IDS
	: [BANNER_PLACEMENT_ID]

Prompt To Fix With AI

This is a comment left during a code review.
Path: web/src/lib/ad-providers/gravity.ts
Line: 114-128

Comment:
**Simplify placement/variant derivation**

The intermediate `requestedPlacementIds` variable is checked twice with `?.length`, and the `length === 1 ? 'banner' : 'choice'` branch will never be `'banner'` because `WAITING_ROOM_PLACEMENT_IDS` always has 4 entries. Checking `input.surface` directly removes the extra variable and the duplicate guards.

```suggestion
      const variant =
        input.surface === 'waiting_room' ? 'choice' : getGravityVariant(userId)
      const filteredMessages = prepareGravityMessages(messages)

      const placementIds =
        input.surface === 'waiting_room'
          ? WAITING_ROOM_PLACEMENT_IDS
          : variant === 'choice'
            ? CHOICE_PLACEMENT_IDS
            : [BANNER_PLACEMENT_ID]
```

How can I resolve this? If you propose a fix, please make it concise.