fix(ui): only show the previous-question button when a previous question exists

[cat0825]

Closes#2354

问题

AskUserQuestion 弹窗底部操作区始终渲染"上一题"按钮，只用 isDisabled 在 questionIndex === 0 时禁用：

• 单问题模式：questionIndex 恒为 0，按钮永远禁用但一直占据 UI
• 多问题模式第一题：同样显示一个禁用的"上一题"，第一题没有可回的上一题

期望：第一题（含单问题场景）不显示"上一题"；从第二题开始才显示。

修复

packages/ui/src/user-question-prompt.tsx：将无条件渲染 + isDisabled 改为按 questionIndex > 0条件渲染，并去掉冗余的 questionIndex === 0 禁用判断（渲染条件已保证"有题可回"）。

测试

• SSR 单测（conversation-localization.test.tsx，+2）：单问题不渲染 上一题/Previous；多问题首题不渲染
• e2e（ask-user-question.spec.ts，扩展三题流程）：首题按钮 toHaveCount(0)；次题出现"上一题"，点击回退后已选答案保留、按钮消失，再前进继续原流程
• 本地验证：packages/ui 444/444 通过；ask-user-question.spec.ts 2/2 通过（Playwright + Electron）；biome 干净

行为对照

场景	修复前	修复后
单个问题	禁用"上一题"常驻	不显示
多问题·第一题	禁用"上一题"常驻	不显示
多问题·第二题起	可用"上一题"	可用"上一题"（不变）

[Astro-Han]

Thanks — the core condition is right (questionIndex > 0, and the array is dense so it always equals 'a previous question exists'), the request event is atomic so streaming can't half-populate it, and the e2e pins the Q1-hidden/Q2-shown contract including 'not a disabled one'. CI green.

Four optional nits:

• One-frame dirty render on session switch: staying on index>0 then switching sessions renders one frame of the new request's question with the old draft + previous button, before the effect resets. Pure visual (the click gets reset anyway), but a key={requestId} remount or an effect-less derivation would kill it.
• Narrow containers: the footer grid moves 下一题 from col2 to col3 on Q2, so a fast double-click on the first question lands on the newly-appeared 上一题 and pops back — looks broken on ≤460px. Desktop width is fine (col4 is pinned).
• Back-navigation focus is unpinned: only the forward direction has a toBeFocused assertion; the return path drops focus to body (same as before this PR, just untested).
• The reset effect itself has zero coverage: unit tests only render index 0; a future refactor that breaks the sync would pass everything. One component test (advance to index>0, swap props.request, assert reset) would pin it cheaply.

Merging.

[cat0825]

Closes#2354

问题

AskUserQuestion 弹窗底部操作区始终渲染"上一题"按钮，只用 isDisabled 在 questionIndex === 0 时禁用：

• 单问题模式：questionIndex 恒为 0，按钮永远禁用但一直占据 UI
• 多问题模式第一题：同样显示一个禁用的"上一题"，第一题没有可回的上一题

期望：第一题（含单问题场景）不显示"上一题"；从第二题开始才显示。

修复

packages/ui/src/user-question-prompt.tsx：将无条件渲染 + isDisabled 改为按 questionIndex > 0条件渲染，并去掉冗余的 questionIndex === 0 禁用判断（渲染条件已保证"有题可回"）。

测试

• SSR 单测（conversation-localization.test.tsx，+2）：单问题不渲染 上一题/Previous；多问题首题不渲染
• e2e（ask-user-question.spec.ts，扩展三题流程）：首题按钮 toHaveCount(0)；次题出现"上一题"，点击回退后已选答案保留、按钮消失，再前进继续原流程
• 本地验证：packages/ui 444/444 通过；ask-user-question.spec.ts 2/2 通过（Playwright + Electron）；biome 干净

行为对照

场景	修复前	修复后
单个问题	禁用"上一题"常驻	不显示
多问题·第一题	禁用"上一题"常驻	不显示
多问题·第二题起	可用"上一题"	可用"上一题"（不变）

[Astro-Han]

Thanks — the core condition is right (questionIndex > 0, and the array is dense so it always equals 'a previous question exists'), the request event is atomic so streaming can't half-populate it, and the e2e pins the Q1-hidden/Q2-shown contract including 'not a disabled one'. CI green.

Four optional nits:

• One-frame dirty render on session switch: staying on index>0 then switching sessions renders one frame of the new request's question with the old draft + previous button, before the effect resets. Pure visual (the click gets reset anyway), but a key={requestId} remount or an effect-less derivation would kill it.
• Narrow containers: the footer grid moves 下一题 from col2 to col3 on Q2, so a fast double-click on the first question lands on the newly-appeared 上一题 and pops back — looks broken on ≤460px. Desktop width is fine (col4 is pinned).
• Back-navigation focus is unpinned: only the forward direction has a toBeFocused assertion; the return path drops focus to body (same as before this PR, just untested).
• The reset effect itself has zero coverage: unit tests only render index 0; a future refactor that breaks the sync would pass everything. One component test (advance to index>0, swap props.request, assert reset) would pin it cheaply.

Merging.

[cat0825]

Closes#2354

问题

AskUserQuestion 弹窗底部操作区始终渲染"上一题"按钮，只用 isDisabled 在 questionIndex === 0 时禁用：

• 单问题模式：questionIndex 恒为 0，按钮永远禁用但一直占据 UI
• 多问题模式第一题：同样显示一个禁用的"上一题"，第一题没有可回的上一题

期望：第一题（含单问题场景）不显示"上一题"；从第二题开始才显示。

修复

packages/ui/src/user-question-prompt.tsx：将无条件渲染 + isDisabled 改为按 questionIndex > 0条件渲染，并去掉冗余的 questionIndex === 0 禁用判断（渲染条件已保证"有题可回"）。

测试

• SSR 单测（conversation-localization.test.tsx，+2）：单问题不渲染 上一题/Previous；多问题首题不渲染
• e2e（ask-user-question.spec.ts，扩展三题流程）：首题按钮 toHaveCount(0)；次题出现"上一题"，点击回退后已选答案保留、按钮消失，再前进继续原流程
• 本地验证：packages/ui 444/444 通过；ask-user-question.spec.ts 2/2 通过（Playwright + Electron）；biome 干净

行为对照

场景	修复前	修复后
单个问题	禁用"上一题"常驻	不显示
多问题·第一题	禁用"上一题"常驻	不显示
多问题·第二题起	可用"上一题"	可用"上一题"（不变）

[Astro-Han]

Thanks — the core condition is right (questionIndex > 0, and the array is dense so it always equals 'a previous question exists'), the request event is atomic so streaming can't half-populate it, and the e2e pins the Q1-hidden/Q2-shown contract including 'not a disabled one'. CI green.

Four optional nits:

• One-frame dirty render on session switch: staying on index>0 then switching sessions renders one frame of the new request's question with the old draft + previous button, before the effect resets. Pure visual (the click gets reset anyway), but a key={requestId} remount or an effect-less derivation would kill it.
• Narrow containers: the footer grid moves 下一题 from col2 to col3 on Q2, so a fast double-click on the first question lands on the newly-appeared 上一题 and pops back — looks broken on ≤460px. Desktop width is fine (col4 is pinned).
• Back-navigation focus is unpinned: only the forward direction has a toBeFocused assertion; the return path drops focus to body (same as before this PR, just untested).
• The reset effect itself has zero coverage: unit tests only render index 0; a future refactor that breaks the sync would pass everything. One component test (advance to index>0, swap props.request, assert reset) would pin it cheaply.

Merging.

[cat0825]

Closes#2354

问题

AskUserQuestion 弹窗底部操作区始终渲染"上一题"按钮，只用 isDisabled 在 questionIndex === 0 时禁用：

• 单问题模式：questionIndex 恒为 0，按钮永远禁用但一直占据 UI
• 多问题模式第一题：同样显示一个禁用的"上一题"，第一题没有可回的上一题

期望：第一题（含单问题场景）不显示"上一题"；从第二题开始才显示。

修复

packages/ui/src/user-question-prompt.tsx：将无条件渲染 + isDisabled 改为按 questionIndex > 0条件渲染，并去掉冗余的 questionIndex === 0 禁用判断（渲染条件已保证"有题可回"）。

测试

• SSR 单测（conversation-localization.test.tsx，+2）：单问题不渲染 上一题/Previous；多问题首题不渲染
• e2e（ask-user-question.spec.ts，扩展三题流程）：首题按钮 toHaveCount(0)；次题出现"上一题"，点击回退后已选答案保留、按钮消失，再前进继续原流程
• 本地验证：packages/ui 444/444 通过；ask-user-question.spec.ts 2/2 通过（Playwright + Electron）；biome 干净

行为对照

场景	修复前	修复后
单个问题	禁用"上一题"常驻	不显示
多问题·第一题	禁用"上一题"常驻	不显示
多问题·第二题起	可用"上一题"	可用"上一题"（不变）

[Astro-Han]

Thanks — the core condition is right (questionIndex > 0, and the array is dense so it always equals 'a previous question exists'), the request event is atomic so streaming can't half-populate it, and the e2e pins the Q1-hidden/Q2-shown contract including 'not a disabled one'. CI green.

Four optional nits:

• One-frame dirty render on session switch: staying on index>0 then switching sessions renders one frame of the new request's question with the old draft + previous button, before the effect resets. Pure visual (the click gets reset anyway), but a key={requestId} remount or an effect-less derivation would kill it.
• Narrow containers: the footer grid moves 下一题 from col2 to col3 on Q2, so a fast double-click on the first question lands on the newly-appeared 上一题 and pops back — looks broken on ≤460px. Desktop width is fine (col4 is pinned).
• Back-navigation focus is unpinned: only the forward direction has a toBeFocused assertion; the return path drops focus to body (same as before this PR, just untested).
• The reset effect itself has zero coverage: unit tests only render index 0; a future refactor that breaks the sync would pass everything. One component test (advance to index>0, swap props.request, assert reset) would pin it cheaply.

Merging.

[cat0825]

Closes#2354

问题

AskUserQuestion 弹窗底部操作区始终渲染"上一题"按钮，只用 isDisabled 在 questionIndex === 0 时禁用：

• 单问题模式：questionIndex 恒为 0，按钮永远禁用但一直占据 UI
• 多问题模式第一题：同样显示一个禁用的"上一题"，第一题没有可回的上一题

期望：第一题（含单问题场景）不显示"上一题"；从第二题开始才显示。

修复

packages/ui/src/user-question-prompt.tsx：将无条件渲染 + isDisabled 改为按 questionIndex > 0条件渲染，并去掉冗余的 questionIndex === 0 禁用判断（渲染条件已保证"有题可回"）。

测试

• SSR 单测（conversation-localization.test.tsx，+2）：单问题不渲染 上一题/Previous；多问题首题不渲染
• e2e（ask-user-question.spec.ts，扩展三题流程）：首题按钮 toHaveCount(0)；次题出现"上一题"，点击回退后已选答案保留、按钮消失，再前进继续原流程
• 本地验证：packages/ui 444/444 通过；ask-user-question.spec.ts 2/2 通过（Playwright + Electron）；biome 干净

行为对照

场景	修复前	修复后
单个问题	禁用"上一题"常驻	不显示
多问题·第一题	禁用"上一题"常驻	不显示
多问题·第二题起	可用"上一题"	可用"上一题"（不变）

[Astro-Han]

Thanks — the core condition is right (questionIndex > 0, and the array is dense so it always equals 'a previous question exists'), the request event is atomic so streaming can't half-populate it, and the e2e pins the Q1-hidden/Q2-shown contract including 'not a disabled one'. CI green.

Four optional nits:

• One-frame dirty render on session switch: staying on index>0 then switching sessions renders one frame of the new request's question with the old draft + previous button, before the effect resets. Pure visual (the click gets reset anyway), but a key={requestId} remount or an effect-less derivation would kill it.
• Narrow containers: the footer grid moves 下一题 from col2 to col3 on Q2, so a fast double-click on the first question lands on the newly-appeared 上一题 and pops back — looks broken on ≤460px. Desktop width is fine (col4 is pinned).
• Back-navigation focus is unpinned: only the forward direction has a toBeFocused assertion; the return path drops focus to body (same as before this PR, just untested).
• The reset effect itself has zero coverage: unit tests only render index 0; a future refactor that breaks the sync would pass everything. One component test (advance to index>0, swap props.request, assert reset) would pin it cheaply.

Merging.

[cat0825]

Closes#2354

问题

AskUserQuestion 弹窗底部操作区始终渲染"上一题"按钮，只用 isDisabled 在 questionIndex === 0 时禁用：

• 单问题模式：questionIndex 恒为 0，按钮永远禁用但一直占据 UI
• 多问题模式第一题：同样显示一个禁用的"上一题"，第一题没有可回的上一题

期望：第一题（含单问题场景）不显示"上一题"；从第二题开始才显示。

修复

packages/ui/src/user-question-prompt.tsx：将无条件渲染 + isDisabled 改为按 questionIndex > 0条件渲染，并去掉冗余的 questionIndex === 0 禁用判断（渲染条件已保证"有题可回"）。

测试

• SSR 单测（conversation-localization.test.tsx，+2）：单问题不渲染 上一题/Previous；多问题首题不渲染
• e2e（ask-user-question.spec.ts，扩展三题流程）：首题按钮 toHaveCount(0)；次题出现"上一题"，点击回退后已选答案保留、按钮消失，再前进继续原流程
• 本地验证：packages/ui 444/444 通过；ask-user-question.spec.ts 2/2 通过（Playwright + Electron）；biome 干净

行为对照

场景	修复前	修复后
单个问题	禁用"上一题"常驻	不显示
多问题·第一题	禁用"上一题"常驻	不显示
多问题·第二题起	可用"上一题"	可用"上一题"（不变）

[Astro-Han]

Thanks — the core condition is right (questionIndex > 0, and the array is dense so it always equals 'a previous question exists'), the request event is atomic so streaming can't half-populate it, and the e2e pins the Q1-hidden/Q2-shown contract including 'not a disabled one'. CI green.

Four optional nits:

• One-frame dirty render on session switch: staying on index>0 then switching sessions renders one frame of the new request's question with the old draft + previous button, before the effect resets. Pure visual (the click gets reset anyway), but a key={requestId} remount or an effect-less derivation would kill it.
• Narrow containers: the footer grid moves 下一题 from col2 to col3 on Q2, so a fast double-click on the first question lands on the newly-appeared 上一题 and pops back — looks broken on ≤460px. Desktop width is fine (col4 is pinned).
• Back-navigation focus is unpinned: only the forward direction has a toBeFocused assertion; the return path drops focus to body (same as before this PR, just untested).
• The reset effect itself has zero coverage: unit tests only render index 0; a future refactor that breaks the sync would pass everything. One component test (advance to index>0, swap props.request, assert reset) would pin it cheaply.

Merging.

[cat0825]

Closes#2354

问题

AskUserQuestion 弹窗底部操作区始终渲染"上一题"按钮，只用 isDisabled 在 questionIndex === 0 时禁用：

• 单问题模式：questionIndex 恒为 0，按钮永远禁用但一直占据 UI
• 多问题模式第一题：同样显示一个禁用的"上一题"，第一题没有可回的上一题

期望：第一题（含单问题场景）不显示"上一题"；从第二题开始才显示。

修复

packages/ui/src/user-question-prompt.tsx：将无条件渲染 + isDisabled 改为按 questionIndex > 0条件渲染，并去掉冗余的 questionIndex === 0 禁用判断（渲染条件已保证"有题可回"）。

测试

• SSR 单测（conversation-localization.test.tsx，+2）：单问题不渲染 上一题/Previous；多问题首题不渲染
• e2e（ask-user-question.spec.ts，扩展三题流程）：首题按钮 toHaveCount(0)；次题出现"上一题"，点击回退后已选答案保留、按钮消失，再前进继续原流程
• 本地验证：packages/ui 444/444 通过；ask-user-question.spec.ts 2/2 通过（Playwright + Electron）；biome 干净

行为对照

场景	修复前	修复后
单个问题	禁用"上一题"常驻	不显示
多问题·第一题	禁用"上一题"常驻	不显示
多问题·第二题起	可用"上一题"	可用"上一题"（不变）

[Astro-Han]

Thanks — the core condition is right (questionIndex > 0, and the array is dense so it always equals 'a previous question exists'), the request event is atomic so streaming can't half-populate it, and the e2e pins the Q1-hidden/Q2-shown contract including 'not a disabled one'. CI green.

Four optional nits:

• One-frame dirty render on session switch: staying on index>0 then switching sessions renders one frame of the new request's question with the old draft + previous button, before the effect resets. Pure visual (the click gets reset anyway), but a key={requestId} remount or an effect-less derivation would kill it.
• Narrow containers: the footer grid moves 下一题 from col2 to col3 on Q2, so a fast double-click on the first question lands on the newly-appeared 上一题 and pops back — looks broken on ≤460px. Desktop width is fine (col4 is pinned).
• Back-navigation focus is unpinned: only the forward direction has a toBeFocused assertion; the return path drops focus to body (same as before this PR, just untested).
• The reset effect itself has zero coverage: unit tests only render index 0; a future refactor that breaks the sync would pass everything. One component test (advance to index>0, swap props.request, assert reset) would pin it cheaply.

Merging.

[cat0825]

Closes#2354

问题

AskUserQuestion 弹窗底部操作区始终渲染"上一题"按钮，只用 isDisabled 在 questionIndex === 0 时禁用：

• 单问题模式：questionIndex 恒为 0，按钮永远禁用但一直占据 UI
• 多问题模式第一题：同样显示一个禁用的"上一题"，第一题没有可回的上一题

期望：第一题（含单问题场景）不显示"上一题"；从第二题开始才显示。

修复

packages/ui/src/user-question-prompt.tsx：将无条件渲染 + isDisabled 改为按 questionIndex > 0条件渲染，并去掉冗余的 questionIndex === 0 禁用判断（渲染条件已保证"有题可回"）。

测试

• SSR 单测（conversation-localization.test.tsx，+2）：单问题不渲染 上一题/Previous；多问题首题不渲染
• e2e（ask-user-question.spec.ts，扩展三题流程）：首题按钮 toHaveCount(0)；次题出现"上一题"，点击回退后已选答案保留、按钮消失，再前进继续原流程
• 本地验证：packages/ui 444/444 通过；ask-user-question.spec.ts 2/2 通过（Playwright + Electron）；biome 干净

行为对照

场景	修复前	修复后
单个问题	禁用"上一题"常驻	不显示
多问题·第一题	禁用"上一题"常驻	不显示
多问题·第二题起	可用"上一题"	可用"上一题"（不变）

[Astro-Han]

Thanks — the core condition is right (questionIndex > 0, and the array is dense so it always equals 'a previous question exists'), the request event is atomic so streaming can't half-populate it, and the e2e pins the Q1-hidden/Q2-shown contract including 'not a disabled one'. CI green.

Four optional nits:

• One-frame dirty render on session switch: staying on index>0 then switching sessions renders one frame of the new request's question with the old draft + previous button, before the effect resets. Pure visual (the click gets reset anyway), but a key={requestId} remount or an effect-less derivation would kill it.
• Narrow containers: the footer grid moves 下一题 from col2 to col3 on Q2, so a fast double-click on the first question lands on the newly-appeared 上一题 and pops back — looks broken on ≤460px. Desktop width is fine (col4 is pinned).
• Back-navigation focus is unpinned: only the forward direction has a toBeFocused assertion; the return path drops focus to body (same as before this PR, just untested).
• The reset effect itself has zero coverage: unit tests only render index 0; a future refactor that breaks the sync would pass everything. One component test (advance to index>0, swap props.request, assert reset) would pin it cheaply.

Merging.