fix(installer): preserve USER-PROFILE.md and dev-preferences.md on re-install (#1945)

Running gsd-update (re-running the installer) silently deleted two
user-generated files:
- get-shit-done/USER-PROFILE.md (created by /gsd-profile-user)
- commands/gsd/dev-preferences.md (created by /gsd-profile-user)

Root causes:
1. copyWithPathReplacement() calls fs.rmSync(destDir, {recursive:true})
   before copying, wiping USER-PROFILE.md with no preserve allowlist.
2. The legacy commands/gsd/ cleanup at ~line 5211 rmSync'd the entire
   directory, wiping dev-preferences.md.
3. The backup path in profile-user.md pointed to the same directory
   that gets wiped, so the backup was also lost.

Fix:
- Add preserveUserArtifacts(destDir, fileNames) and restoreUserArtifacts()
  helpers that save/restore listed files around destructive wipes.
- Call them in install() before the get-shit-done/ copy (preserves
  USER-PROFILE.md) and before the legacy commands/gsd/ cleanup
  (preserves dev-preferences.md).
- Fix profile-user.md backup path from ~/.claude/get-shit-done/USER-PROFILE.backup.md
  to ~/.claude/USER-PROFILE.backup.md (outside the wiped directory).

Closes #1924

Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>

bin/install.js

@@ -3809,6 +3809,42 @@ function copyCommandsAsAntigravitySkills(srcDir, skillsDir, prefix, isGlobal = f
   recurse(srcDir, prefix);
 }
 
+/**
+ * Save user-generated files from destDir to an in-memory map before a wipe.
+ *
+ * @param {string} destDir - Directory that is about to be wiped
+ * @param {string[]} fileNames - Relative file names (e.g. ['USER-PROFILE.md']) to preserve
+ * @returns {Map<string, string>} Map of fileName → file content (only entries that existed)
+ */
+function preserveUserArtifacts(destDir, fileNames) {
+  const saved = new Map();
+  for (const name of fileNames) {
+    const fullPath = path.join(destDir, name);
+    if (fs.existsSync(fullPath)) {
+      try {
+        saved.set(name, fs.readFileSync(fullPath, 'utf8'));
+      } catch { /* skip unreadable files */ }
+    }
+  }
+  return saved;
+}
+
+/**
+ * Restore user-generated files saved by preserveUserArtifacts after a wipe.
+ *
+ * @param {string} destDir - Directory that was wiped and recreated
+ * @param {Map<string, string>} saved - Map returned by preserveUserArtifacts
+ */
+function restoreUserArtifacts(destDir, saved) {
+  for (const [name, content] of saved) {
+    const fullPath = path.join(destDir, name);
+    try {
+      fs.mkdirSync(path.dirname(fullPath), { recursive: true });
+      fs.writeFileSync(fullPath, content, 'utf8');
+    } catch { /* skip unwritable paths */ }
+  }
+}
+
 /**
  * Recursively copy directory, replacing paths in .md files
  * Deletes existing destDir first to remove orphaned files from previous versions
@@ -5217,10 +5253,13 @@ function install(isGlobal, runtime = 'claude') {
     }
 
     // Clean up legacy commands/gsd/ from previous global installs
+    // Preserve user-generated files (dev-preferences.md) before wiping the directory
     const legacyCommandsDir = path.join(targetDir, 'commands', 'gsd');
     if (fs.existsSync(legacyCommandsDir)) {
+      const savedLegacyArtifacts = preserveUserArtifacts(legacyCommandsDir, ['dev-preferences.md']);
       fs.rmSync(legacyCommandsDir, { recursive: true });
       console.log(`  ${green}✓${reset} Removed legacy commands/gsd/ directory`);
+      restoreUserArtifacts(legacyCommandsDir, savedLegacyArtifacts);
     }
   } else {
     // Claude Code local: commands/gsd/ format — Claude Code reads local project
@@ -5252,9 +5291,12 @@ function install(isGlobal, runtime = 'claude') {
   }
 
   // Copy get-shit-done skill with path replacement
+  // Preserve user-generated files before the wipe-and-copy so they survive re-install
   const skillSrc = path.join(src, 'get-shit-done');
   const skillDest = path.join(targetDir, 'get-shit-done');
+  const savedGsdArtifacts = preserveUserArtifacts(skillDest, ['USER-PROFILE.md']);
   copyWithPathReplacement(skillSrc, skillDest, pathPrefix, runtime, false, isGlobal);
+  restoreUserArtifacts(skillDest, savedGsdArtifacts);
   if (verifyInstalled(skillDest, 'get-shit-done')) {
     console.log(`  ${green}✓${reset} Installed get-shit-done`);
   } else {
@@ -6172,6 +6214,8 @@ if (process.env.GSD_TEST_MODE) {
     writeManifest,
     reportLocalPatches,
     validateHookFields,
+    preserveUserArtifacts,
+    restoreUserArtifacts,
   };
 } else {