fix(installer): resolve directory path to an absolute path

Ensures that the installation directory is always resolved to an absolute path.

Previously, if a relative path like '.' was used, its interpretation could vary depending on the execution context of the script. This change uses `path.resolve` with `process.cwd()` as a fallback to guarantee a consistent and predictable absolute path for the installation directory.

tools/installer/bin/bmad.js

@@ -71,7 +71,7 @@ program
 
         const config = {
           installType,
-          directory: options.directory || '.',
+          directory: path.resolve(options.directory || process.cwd()),
           ides: (options.ide || []).filter((ide) => ide !== 'other'),
           expansionPacks: options.expansionPacks || [],
         };