fix: BMAD install creates .bmad-core/.bmad-core/ directory structure + updates (#223)

* chore: fix installation directory handling to use .bmad-core as default path

- Remove redundant ./ prefix from default directory
- Update all default paths from ./.bmad-core to .bmad-core
- Add logic to handle direct .bmad-core path selection
- Treat parent as project root when .bmad-core specified
- Simplify directory state detection for existing files
- Remove unknown_existing state type from installer logic

* chore: refactor installer to use modern JS patterns and improve code clarity

## CHANGES

- Replace require with node:path import
- Add block scoping to switch cases
- Remove unused options parameter from update
- Use optional chaining for ideConfig check
- Replace forEach with for...of loops
- Use template literals for string concatenation
- Add early return to avoid else block
- Update spell check dictionary entries

* chore: update dependencies to latest major versions

## CHANGES

- Update @kayvan/markdown-tree-parser to v1.5.0
- Update chalk to v5.4.1 for ESM support
- Update commander to v14.0.0 with Node 20 requirement
- Update fs-extra to v11.3.0
- Update glob to v11.0.3 with new API
- Update inquirer to v12.6.3 with modular design
- Update ora to v8.2.0 with improved features

tools/installer/bin/bmad.js

@@ -37,7 +37,7 @@ program
   .description('Install BMAD Method agents and tools')
   .option('-f, --full', 'Install complete .bmad-core folder')
   .option('-a, --agent <agent>', 'Install specific agent with dependencies')
-  .option('-d, --directory <path>', 'Installation directory (default: ./bmad-core)')
+  .option('-d, --directory <path>', 'Installation directory (default: .bmad-core)')
   .option('-i, --ide <ide>', 'Configure for specific IDE (cursor, claude-code, windsurf, roo)')
   .action(async (options) => {
     try {
@@ -50,7 +50,7 @@ program
         const config = {
           installType: options.full ? 'full' : 'single-agent',
           agent: options.agent,
-          directory: options.directory || './.bmad-core',
+          directory: options.directory || '.bmad-core',
           ide: options.ide
         };
         await installer.install(config);
@@ -66,9 +66,9 @@ program
   .description('Update existing BMAD installation')
   .option('--force', 'Force update, overwriting modified files')
   .option('--dry-run', 'Show what would be updated without making changes')
-  .action(async (options) => {
+  .action(async () => {
     try {
-      await installer.update(options);
+      await installer.update();
     } catch (error) {
       console.error(chalk.red('Update failed:'), error.message);
       process.exit(1);
@@ -110,7 +110,7 @@ async function promptInstallation() {
       type: 'input',
       name: 'directory',
       message: 'Where would you like to install BMAD?',
-      default: './.bmad-core'
+      default: '.bmad-core'
     }
   ]);
   answers.directory = directory;