[asdf80730]

Draft: depends on #975. Do not mark ready or merge before #975 lands.

Summary

 installer/installer.nsi
-  Function ensureVCRedist            # 47 lines
-  Call ensureVCRedist                # TODO + comment + call
-  !addplugindir ... inetc            # 3 lines
 installer/macros.nsh
-  DownloadAndInstallVCRedist macro   # 40 lines
 installer/locale/{English,SimpChinese,TradChinese}.nsh
-  DOWNLOAD_VCREDIST_QUESTION / DOWNLOAD_VCREDIST_FAILED_MESSAGE / INST_VCREDIST_FAILED_MESSAGE
 installer/inetc/**                   # 39 vendored files

The check was a Windows 7/8.1 relic. Windows 10 is the minimum supported OS,
so ucrtbase.dll is in-box. After the launcher links the MSVC CRT statically
(#975), no shipped binary imports a redistributable DLL: the only
vcruntime140.dll is python\python3\vcruntime140.dll, which the interpreter
loads from its own directory. The check tested msvcp140.dll, which no shipped
binary imports, and its download prompt aborted offline installations before
anything was copied.

inetc had no caller outside the deleted macro, so the plugin and its
!addplugindir line go too. StdUtils is a separate plugin and stays.

Depends on #975. Without it, removing this check leaves the launcher without
VCRUNTIME140.dll on a clean machine. Merge #975 first.

Closes #966.

Verification

Fork CI run 39446806581:
build.bat, the launcher dependency gate and makensis all pass. Static
checks: git grep -E 'VCREDIST|vc_redist' -- installer and
git grep inetc -- installer return nothing.

Generated with assistance from omp (DeepSeek V4.1 Flash).

[asdf80730]

This is stacked on #975: removing the redistributable bootstrap only holds once the
launcher no longer imports VCRUNTIME140.dll. #983 reproduces the failure mode on Windows
11 ARM64 today — the x86 launcher loads an ARM64 vcruntime140.dll from PATH and dies
with 0xc000007b, and the installer never placed the x86 runtime there.

[PCMan]

This is the correct architectural fix for #966. Since Windows 10 is the minimum supported OS (Universal CRT is in-box), all native binaries link statically with /MT (and #975 links the launcher), the entire Win7/8-era ensureVCRedist check, translation strings, and the 39 vendored inetc files can be safely deleted. Ready to land once #975 is merged. LGTM!

(Review comment generated with assistance from Antigravity + Gemini 3.8 Flash)