Merge upstream/main (#2710 one test binary per crate, #2713) into round3a-integration

Conflicts:
- xtask/src/main.rs: upstream's runners (cargo test or nextest, no
  examples, doctests apart, one wasm `cargo check --keep-going`) with
  #2302's `ci --quick` on top: test_selected builds the same targets
  (--lib --bins --tests), the wasm check takes the changed crates in one
  call, the full test step is upstream's.
- apps/lightcraft/src/control_server.rs: upstream's `before` closure, with
  the batch's no-delay sockets kept.
- docs/parity-checklist.md: LR-BEHAV-ACCESS from main (tests/it path),
  LR-BEHAV-LOCALE / LR-BEHAV-LOCALIZE from the batch (Polish).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

README.zh-hans.md

@@ -357,7 +357,7 @@ CI 默认使用行表调试信息，并按启动时可用内存每 1.5 GB 开一
 （每个 CPU 最多一个；读不到内存时为 4 个），所以一台 8 GB、空闲 6 GB 的机器会用 4 个任务构建，
 而一台空闲内存很少的繁忙机器会用更少。测试线程数随之调整，上限为 4。否则，每个 CPU 一个的
 完整调试信息链接器会在任何测试运行之前就耗尽内存。GPU 覆盖范围不变。显式设置
-`CARGO_PROFILE_DEV_DEBUG`、`CARGO_BUILD_JOBS` 和 `RUST_TEST_THREADS` 会覆盖这些默认值。
+`CARGO_PROFILE_DEV_DEBUG`、`CARGO_BUILD_JOBS`、`RUST_TEST_THREADS` 和 `NEXTEST_TEST_THREADS` 会覆盖这些默认值。
 日常开发命令保持它们各自的设置。
 
 **内存受限机器上的 release 构建：** [#1196](https://github.com/storytold/lightcraft/issues/1196)