feat: add Choice Ad placement type with 50/50 A/B test

Introduces a new "Choice Ad" placement that shows 4 ads as
side-by-side cards instead of a single banner. Users are
deterministically assigned to either the existing banner or the new
choice variant via a hash of their userId (50/50 split).

Backend: requests 4 placement IDs (choice-ad-1 through choice-ad-4)
from Gravity API for the choice variant. All returned ads are stored
to ad_impression and impressions fire for each card.

Client: new ChoiceAdBanner component renders equal-width bordered
cards with CTA button + domain per card, hover effects, and
theme-aware styling. Gracefully handles partial fills (1-4 ads).

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: 2 people

cli/src/chat.tsx

@@ -14,6 +14,7 @@ import { useShallow } from 'zustand/react/shallow'
 import { getAdsEnabled, handleAdsDisable } from './commands/ads'
 import { routeUserPrompt, addBashMessageToHistory } from './commands/router'
 import { AdBanner } from './components/ad-banner'
+import { ChoiceAdBanner } from './components/choice-ad-banner'
 import { ChatInputBar } from './components/chat-input-bar'
 import { LoadPreviousButton } from './components/load-previous-button'
 import { ReviewScreen } from './components/review-screen'
@@ -168,7 +169,7 @@ export const Chat = ({
   })
   const hasSubscription = subscriptionData?.hasSubscription ?? false
 
-  const { ad } = useGravityAd({ enabled: IS_FREEBUFF || !hasSubscription })
+  const { ad, adData } = useGravityAd({ enabled: IS_FREEBUFF || !hasSubscription })
   const [adsManuallyDisabled, setAdsManuallyDisabled] = useState(false)
 
   const handleDisableAds = useCallback(() => {
@@ -1445,11 +1446,19 @@ export const Chat = ({
         )}
 
         {ad && (IS_FREEBUFF || (!adsManuallyDisabled && getAdsEnabled())) && (
-          <AdBanner
-            ad={ad}
-            onDisableAds={handleDisableAds}
-            isFreeMode={IS_FREEBUFF || agentMode === 'FREE'}
-          />
+          adData?.variant === 'choice' ? (
+            <ChoiceAdBanner
+              ads={adData.ads}
+              onDisableAds={handleDisableAds}
+              isFreeMode={IS_FREEBUFF || agentMode === 'FREE'}
+            />
+          ) : (
+            <AdBanner
+              ad={ad}
+              onDisableAds={handleDisableAds}
+              isFreeMode={IS_FREEBUFF || agentMode === 'FREE'}
+            />
+          )
         )}
 
         {reviewMode ? (

cli/src/components/choice-ad-banner.tsx

@@ -0,0 +1,242 @@
+import { TextAttributes } from '@opentui/core'
+import { safeOpen } from '../utils/open-url'
+import React, { useState, useMemo } from 'react'
+
+import { Button } from './button'
+import { Clickable } from './clickable'
+import { useTerminalDimensions } from '../hooks/use-terminal-dimensions'
+import { useTheme } from '../hooks/use-theme'
+import { IS_FREEBUFF } from '../utils/constants'
+
+import type { AdResponse } from '../hooks/use-gravity-ad'
+
+interface ChoiceAdBannerProps {
+  ads: AdResponse[]
+  onDisableAds: () => void
+  isFreeMode: boolean
+}
+
+const CARD_HEIGHT = 5 // border-top + description + spacer + cta row + border-bottom
+
+const extractDomain = (url: string): string => {
+  try {
+    const parsed = new URL(url)
+    return parsed.hostname.replace(/^www\./, '')
+  } catch {
+    return url
+  }
+}
+
+/**
+ * Calculate evenly distributed column widths that sum exactly to availableWidth.
+ * Distributes remainder pixels across the first N columns so there's no gap.
+ */
+function columnWidths(count: number, availableWidth: number): number[] {
+  const base = Math.floor(availableWidth / count)
+  const remainder = availableWidth - base * count
+  return Array.from({ length: count }, (_, i) => base + (i < remainder ? 1 : 0))
+}
+
+export const ChoiceAdBanner: React.FC<ChoiceAdBannerProps> = ({ ads, onDisableAds, isFreeMode }) => {
+  const theme = useTheme()
+  const { separatorWidth, terminalWidth } = useTerminalDimensions()
+  const [hoveredIndex, setHoveredIndex] = useState<number | null>(null)
+  const [showInfoPanel, setShowInfoPanel] = useState(false)
+  const [isAdLabelHovered, setIsAdLabelHovered] = useState(false)
+  const [isHideHovered, setIsHideHovered] = useState(false)
+  const [isCloseHovered, setIsCloseHovered] = useState(false)
+
+  // Available width for cards (terminal minus left/right margin of 1 each)
+  const colAvail = terminalWidth - 2
+  const widths = useMemo(() => columnWidths(ads.length, colAvail), [ads.length, colAvail])
+
+  // Sum of all credits across choice ads
+  const totalCredits = ads.reduce((sum, ad) => sum + (ad.credits ?? 0), 0)
+
+  // Hover colors
+  const hoverBorderColor = theme.link
+  const hoverBgColor = theme.name === 'light' ? '#e8f0fe' : '#1a2332'
+
+  return (
+    <box
+      style={{
+        width: '100%',
+        flexDirection: 'column',
+      }}
+    >
+      {/* Horizontal divider line */}
+      <text style={{ fg: theme.muted }}>{'─'.repeat(terminalWidth)}</text>
+
+      {/* Header: "Sponsored picks" + credits + Ad label */}
+      <box
+        style={{
+          width: '100%',
+          paddingLeft: 1,
+          paddingRight: 1,
+          flexDirection: 'row',
+          justifyContent: 'space-between',
+          alignItems: 'flex-start',
+        }}
+      >
+        <text style={{ fg: theme.muted, attributes: TextAttributes.BOLD }}>Sponsored picks</text>
+        <box style={{ flexDirection: 'row', alignItems: 'center', gap: 2, flexShrink: 0 }}>
+          {!IS_FREEBUFF && totalCredits > 0 && (
+            <text style={{ fg: theme.muted }}>+{totalCredits} credits</text>
+          )}
+          {!IS_FREEBUFF ? (
+            <Clickable
+              onMouseDown={() => setShowInfoPanel(true)}
+              onMouseOver={() => setIsAdLabelHovered(true)}
+              onMouseOut={() => setIsAdLabelHovered(false)}
+            >
+              <text
+                style={{
+                  fg: isAdLabelHovered && !showInfoPanel ? theme.foreground : theme.muted,
+                  flexShrink: 0,
+                }}
+              >
+                {isAdLabelHovered && !showInfoPanel ? 'Ad ?' : '  Ad'}
+              </text>
+            </Clickable>
+          ) : (
+            <text style={{ fg: theme.muted, flexShrink: 0 }}>{'  Ad'}</text>
+          )}
+        </box>
+      </box>
+
+      {/* Card columns */}
+      <box
+        style={{
+          marginLeft: 1,
+          marginRight: 1,
+          flexDirection: 'row',
+        }}
+      >
+        {ads.map((ad, i) => {
+          const isHovered = hoveredIndex === i
+          const domain = extractDomain(ad.url)
+          const ctaText = ad.cta || ad.title || 'Learn more'
+
+          return (
+            <Button
+              key={ad.impUrl}
+              onClick={() => {
+                if (ad.clickUrl) safeOpen(ad.clickUrl)
+              }}
+              onMouseOver={() => setHoveredIndex(i)}
+              onMouseOut={() => setHoveredIndex(null)}
+              style={{
+                width: widths[i],
+                height: CARD_HEIGHT,
+                borderStyle: 'single',
+                borderColor: isHovered ? hoverBorderColor : theme.muted,
+                paddingLeft: 1,
+                paddingRight: 1,
+                flexDirection: 'column',
+                backgroundColor: isHovered ? hoverBgColor : undefined,
+              }}
+            >
+              <text style={{ fg: isHovered ? theme.link : theme.muted, flexShrink: 1 }}>
+                {ad.adText}
+              </text>
+              <box style={{ flexGrow: 1 }} />
+              <box style={{ flexDirection: 'row', columnGap: 1, alignItems: 'center' }}>
+                <text
+                  style={{
+                    fg: theme.name === 'light' ? '#ffffff' : theme.background,
+                    bg: isHovered ? theme.link : theme.muted,
+                    attributes: TextAttributes.BOLD,
+                  }}
+                >
+                  {` ${ctaText} `}
+                </text>
+                <text style={{ fg: theme.muted, attributes: TextAttributes.UNDERLINE }}>
+                  {domain}
+                </text>
+              </box>
+            </Button>
+          )
+        })}
+      </box>
+
+      {/* Info panel: shown when Ad label is clicked */}
+      {showInfoPanel && (
+        <box
+          style={{
+            width: '100%',
+            flexDirection: 'column',
+            gap: 0,
+          }}
+        >
+          <text style={{ fg: theme.muted }}>{' ' + '┄'.repeat(separatorWidth - 2)}</text>
+          <box
+            style={{
+              width: '100%',
+              paddingLeft: 1,
+              paddingRight: 1,
+              flexDirection: 'row',
+              justifyContent: 'space-between',
+              alignItems: 'flex-start',
+            }}
+          >
+            <text style={{ fg: theme.muted, flexShrink: 1 }}>
+              {IS_FREEBUFF
+                ? 'Ads help keep Freebuff free.'
+                : 'Ads are optional and earn you credits on each impression. Feel free to hide them anytime.'}
+            </text>
+            <Button
+              onClick={() => setShowInfoPanel(false)}
+              onMouseOver={() => setIsCloseHovered(true)}
+              onMouseOut={() => setIsCloseHovered(false)}
+            >
+              <text
+                style={{
+                  fg: isCloseHovered ? theme.foreground : theme.muted,
+                  flexShrink: 0,
+                }}
+              >
+                {' ✕'}
+              </text>
+            </Button>
+          </box>
+          <box
+            style={{
+              paddingLeft: 1,
+              paddingRight: 1,
+              flexDirection: 'row',
+              alignItems: 'center',
+              gap: 2,
+            }}
+          >
+            {isFreeMode && !IS_FREEBUFF ? (
+              <text style={{ fg: theme.muted }}>
+                Ads are required in Free mode.
+              </text>
+            ) : (
+              <>
+                <Button
+                  onClick={onDisableAds}
+                  onMouseOver={() => setIsHideHovered(true)}
+                  onMouseOut={() => setIsHideHovered(false)}
+                >
+                  <text
+                    style={{
+                      fg: isHideHovered ? theme.link : theme.muted,
+                      attributes: TextAttributes.UNDERLINE,
+                    }}
+                  >
+                    Hide ads
+                  </text>
+                </Button>
+                <text style={{ fg: theme.muted }}>·</text>
+                <text style={{ fg: theme.muted }}>
+                  Use /ads:enable to show again
+                </text>
+              </>
+            )}
+          </box>
+        </box>
+      )}
+    </box>
+  )
+}