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

.vscode/settings.json

@@ -27,6 +27,7 @@
 		"Luxon",
 		"MERN",
 		"mgmt",
+		"nodir",
 		"Nuxt",
 		"overcommitting",
 		"pasteable",
@@ -58,6 +59,8 @@
 		"Turborepo",
 		"Underserved",
 		"unredacted",
+		"upgrader",
+		"upgraders",
 		"VARCHAR",
 		"venv",
 		"vercel",