refactor(base): 增强配置健壮性与开发体验

- 新增 pacman.conf 管理（Color + ILoveCandy + ParallelDownloads）
- dev 模块改用 decman 原生 user/mimic_login 替代手拼 su -
- dev 模块异常处理改为收集汇总，不再静默吞掉
- install.sh 改用 mktemp + trap 清理临时目录
- 移除 AGENTS.md 中不存在的 wsl.py 引用

system/etc/pacman.conf

@@ -0,0 +1,26 @@
+#
+# /etc/pacman.conf
+#
+
+[options]
+HoldPkg     = pacman glibc
+Architecture = auto
+
+Color
+ILoveCandy
+VerbosePkgLists
+ParallelDownloads = 5
+
+CheckSpace
+
+SigLevel    = Required DatabaseOptional
+LocalFileSigLevel = Optional
+
+[core]
+Include = /etc/pacman.d/mirrorlist
+
+[extra]
+Include = /etc/pacman.d/mirrorlist
+
+# [multilib]
+# Include = /etc/pacman.d/mirrorlist