fix(x-sdk): release XStream reader on early exit

[cc-hearts]

中文版模板 / Chinese template

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🔗 Related Issues

• Closes [sync][P1] x-sdk: 修复 XStream 提前退出时 reader lock 泄漏 (#1970) #142
• Syncs fix(x-sdk): release XStream reader lock on early loop exit ant-design/x#1970 (028b7436a23f0433a635de0dfa3777dbf56515ff)

💡 Background and Solution

XStream acquired a reader for its async iterator without releasing it when a consumer exited a for await...of loop early. This left the stream locked and allowed the underlying source to continue buffering.

This change:

• wraps the read loop in try/finally and distinguishes normal completion from early exit
• cancels unfinished streams on break, return, or consumer errors
• suppresses cancellation failures so they do not replace the consumer's original error
• always releases the reader lock
• covers early exit, cancellation failure, and normal completion with tests

Verification:

• vp test packages/x-sdk/src/x-stream/__tests__/index.test.ts — 3 passed
• vp test — 46 files, 445 tests passed
• vp check packages/x-sdk/src/x-stream/index.ts packages/x-sdk/src/x-stream/__tests__/index.test.ts — passed
• repository-wide vp check formatting passed; lint/type checking is currently blocked by 43 unrelated existing errors outside this change

📝 Change Log

Language	Changelog
🇺🇸 English	Release the XStream reader lock and cancel the underlying stream when async iteration exits early.
🇨🇳 Chinese	修复 XStream 异步迭代提前退出时 reader lock 未释放且底层流继续缓冲的问题。

[cc-hearts]

Review：✅ 修复合理，建议合并

try/finally + completed 标志的组合正确区分了正常结束与提前退出：

• 提前 break / return / throw → completed 仍为 false → reader.cancel() 取消底层流，停止继续缓冲
• 正常读完 → done 分支置 completed = true → 跳过 cancel，只 releaseLock()
• cancel() 包在独立 try/catch 里且吞掉异常，不会覆盖消费者的原始错误 —— 这点很关键，finally 里抛出的异常会替换掉正在传播的异常
• releaseLock() 在 finally 尾部无条件执行，两条路径都释放

四条验收标准都满足。三个测试分别覆盖提前 break、消费者抛错（且断言 cancel 失败时原始错误仍被保留）、正常完整消费，覆盖面完整。

无阻塞问题。