ci(release): M142 发布白名单只留 windows-x64 + 修掉诊断脚本在 -e 下先退出

1) PUBLISH_SLOTS 去掉 windows-arm64：白名单齐全性检查是「名单内少一档就 fail」，
   arm64 连试四轮未成 ⇒ Release 永远 fail、x64 编成功也发不出去。arm64 仍留在矩阵里
   照跑取证（诊断注解保留），红不挡发布；修好后把键加回这一行即可（一行可逆）。

2) 修 M141 自毁 bug：`shell: bash` 是 `bash -eo pipefail`，脚本里的 `set -uo pipefail`
   关不掉 -e，于是 `vc_lib=$(find 不存在的根 | head -n1)` 被 pipefail 判非零后 errexit
   当场退出，一条注解都没打（上一轮只剩 exit code 1）。现在显式 `set +e`、每处探测
   `|| true`、问题记进 ERRORS、4 行实况快照无论齐不齐都先打完，再由显式 exit 定红绿；
   齐全时快照降级为 notice（绿跑也留「探测没坏」的证据）。

3) 新增 arm64 失败收尾注解步骤（`if: failure()`），红在其他步骤时也能说清红在哪、不影响 x64。

4) packaging/README.md §1/§3/§4/§7.5/§9 与 release-notes.md 的 Downloads/Support matrix/
   Install 同步为「当前只发布 windows-x64，arm64 待修」。

packaging/release-notes.md

@@ -11,8 +11,13 @@ Asset names are `<name>_<version>_<platform>_<arch>`, underscore separated — t
 
 | Platform | Asset | Notes |
 | --- | --- | --- |
-| Windows 10/11 x64 | `unlucky-launcher_{{VERSION}}_windows_x64.exe` | single exe, double-click to run |
-| Windows 11 ARM64 | `unlucky-launcher_{{VERSION}}_windows_arm64.exe` | single exe, runs natively on ARM64 Windows |
+| Windows 10/11 x64 | `unlucky-launcher_{{VERSION}}_windows_x64.exe` | single exe, double-click to run; this is also what you run on ARM64 Windows (x64 emulation) |
+
+**Windows ARM64 is not part of this release.** CI still builds it on a native `windows-11-arm` runner for
+evidence, but that slot's toolchain check has not gone green yet, so
+`unlucky-launcher_{{VERSION}}_windows_arm64.exe` is deliberately kept out of the download list and out of
+`SHA256SUMS.txt` instead of handing out a build nobody has verified. `windows-x64` is the only published
+slot; ARM64 rejoins this table as soon as its build is green (one line in the workflow's `PUBLISH_SLOTS`).
 
 **This release ships Windows only, and CI builds Windows only.** The Linux (x64 / arm64) and macOS
 (Apple Silicon / Intel) slots are not built by the release workflow at all — they have not been verified
@@ -21,10 +26,10 @@ stay out of the download list and out of `SHA256SUMS.txt` until that verificatio
 workflow run can build all six slots for that purpose, but the four extra slots are never published. The
 support matrix below marks those slots accordingly.
 
-The Windows assets are bare `.exe` files, so `LICENSE`, `NOTICE` and `README.md` are attached to this
-release next to them: the license terms travel with every download. Slots that ship an archive (Linux /
-macOS, once published) unpack to one top-level directory of the same name holding the binary plus those
-three documents.
+The Windows asset is a bare `.exe`, so `LICENSE`, `NOTICE` and `README.md` are attached to this release
+next to it: the license terms travel with every download. Slots that ship an archive (Linux / macOS, once
+published) unpack to one top-level directory of the same name holding the binary plus those three
+documents.
 
 ## Command line
 
@@ -46,7 +51,7 @@ Published = shipped as a download of **this** release, listed in `SHA256SUMS.txt
 | Platform | Status in this release | Level | Runtime requirements |
 | --- | --- | --- | --- |
 | Windows 10/11 x64 | **published** | first class | nothing beyond the OS (UCRT is part of Win10+) |
-| Windows 11 ARM64 | **published** | first class (launcher artifact) | nothing extra; the launcher runs natively, the game itself runs through the OS x64 emulation layer with an x64 JDK |
+| Windows 11 ARM64 | not published (build chasing, unverified) | first class (launcher artifact) | nothing extra; the launcher runs natively, the game itself runs through the OS x64 emulation layer with an x64 JDK |
 | macOS 12+ Apple Silicon | not built (unverified) | first class (unverified) | nothing; unsigned build, needs the Gatekeeper workaround |
 | macOS 12+ Intel | not built (unverified) | first class (unverified) | same as above |
 | Linux x64, X11 | not built (unverified) | first class (unverified) | `libxkbcommon`, `fontconfig`, `libGL` (or software renderer), `libxcb` |
@@ -56,17 +61,18 @@ Published = shipped as a download of **this** release, listed in `SHA256SUMS.txt
 | Windows 8.1/8/7 | not built | unsupported | the baseline is Windows 10 |
 | Android — Termux + X11 | not built (no CI slot) | experimental, not promised | CLI only and only when built from source; GUI unverified |
 
-Both arm64 rows are formal matrix slots, not the experimental Termux path: Windows ARM64 ships here and
-is cross-built with the same static-CRT gate as x64; Linux arm64 is kept as a matrix slot but is not built
-by default — someone has to run it on real hardware (via a manual all-slots run) before it joins this list.
-The rows above and the matrix table in `packaging/README.md` §9 are the same list — change one, change the other.
+`windows-x64` is the only published slot this release; Windows ARM64 is kept out until its build is green
+(see Downloads above). Both arm64 rows are formal matrix slots, not the experimental Termux path, and
+Linux arm64 is not built by default — someone has to run it on real hardware (via a manual all-slots run)
+before it joins this list. The rows above and the matrix table in `packaging/README.md` §9 are the same
+list — change one, change the other.
 
 ## Install
 
-**Windows** — put the `.exe` anywhere and run it (pick `_windows_arm64.exe` on ARM64 Windows,
-`_windows_x64.exe` everywhere else). The first run creates `.ULL/` and `.minecraft/` next to the exe
-(portable is the default data mode); the per-user `%APPDATA%\ULL` plus `%APPDATA%\.minecraft`, or a
-custom root, are selectable instead.
+**Windows** — put the `.exe` anywhere and run it. `_windows_x64.exe` is the only Windows asset in this
+release, and it is also what you run on ARM64 Windows (the OS runs it through its x64 emulation layer).
+The first run creates `.ULL/` and `.minecraft/` next to the exe (portable is the default data mode); the
+per-user `%APPDATA%\ULL` plus `%APPDATA%\.minecraft`, or a custom root, are selectable instead.
 
 Linux / macOS are not part of this release; their asset names are already fixed by the same rule
 (`unlucky-launcher_{{VERSION}}_linux_x64.tar.gz`, `_linux_arm64`, `_macos_arm64`, `_macos_x64`) so the