fix: use $HOME instead of ~ in installed shell command paths (#1284)

The installer pathPrefix for global installs replaced os.homedir()
with ~, which does NOT expand inside double-quoted shell commands
in POSIX shells. This caused MODULE_NOT_FOUND errors when executing
commands like: node "~/.claude/get-shit-done/bin/gsd-tools.cjs"

Changed pathPrefix to use $HOME instead of ~, which correctly expands
inside double quotes. Also fixed a quoted-tilde instance in do.md.

- bin/install.js: $HOME prefix instead of ~ for global installs
- get-shit-done/workflows/do.md: node "$HOME/..." instead of "~/"
- tests/path-replacement.test.cjs: updated + 3 new regression tests

Closes #1284

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

bin/install.js

@@ -3668,12 +3668,14 @@ function install(isGlobal, runtime = 'claude') {
 
   // Path prefix for file references in markdown content (e.g. gsd-tools.cjs).
   // Replaces $HOME/.claude/ or ~/.claude/ so the result is <pathPrefix>get-shit-done/bin/...
-  // For global installs: use ~/ so paths work across environments (e.g. Docker
-  // containers mounting ~/.claude from a Windows host where os.homedir() differs).
+  // For global installs: use $HOME/ so paths expand correctly inside double-quoted
+  // shell commands (~ does NOT expand inside double quotes, causing MODULE_NOT_FOUND).
   // For local installs: use resolved absolute path (may be outside $HOME).
-  const pathPrefix = isGlobal
-    ? path.resolve(targetDir).replace(os.homedir(), '~').replace(/\\/g, '/') + '/'
-    : `${path.resolve(targetDir).replace(/\\/g, '/')}/`;
+  const resolvedTarget = path.resolve(targetDir).replace(/\\/g, '/');
+  const homeDir = os.homedir().replace(/\\/g, '/');
+  const pathPrefix = isGlobal && resolvedTarget.startsWith(homeDir)
+    ? '$HOME' + resolvedTarget.slice(homeDir.length) + '/'
+    : `${resolvedTarget}/`;
 
   let runtimeLabel = 'Claude Code';
   if (isOpencode) runtimeLabel = 'OpenCode';