refactor(mise): let mise enable Corepack, drop the brew entry

Brewfile

@@ -26,7 +26,6 @@ brew "postgresql"
 # Dev / build
 brew "bfg"
 brew "cfn-lint"
-brew "corepack"
 brew "gcc"
 brew "gh"
 brew "git"

bin/install-software.sh

@@ -160,10 +160,10 @@ fi
 section "mise runtimes"
 mise install
 
-# 8. Yarn via Corepack (Node ships with Corepack; per-project pinning via
-# packageManager).
+# 8. Yarn via Corepack. mise enables Corepack itself (settings.node.corepack);
+# this step only prepopulates a global Yarn so first use doesn't block on a
+# download. Per-project pinning still happens via packageManager.
 section "Yarn via Corepack"
-corepack enable
 corepack install -g yarn@stable
 
 # 9. Claude Code CLI. Not in Homebrew; installed via Anthropic's official

dot_config/mise/config.toml

@@ -1,3 +1,6 @@
+[settings]
+node.corepack = true
+
 [tool_alias]
 abtop = "cargo:abtop"
 claudectl = "cargo:claudectl"