* feat: install Cursor rules to subdirectory
Implement feature request #376 to avoid filename collisions and confusion
between repo-specific and BMAD-specific rules.
Changes:
- Move Cursor rules from .cursor/rules/ to .cursor/rules/bmad/
- Update installer configuration to use new subdirectory structure
- Update upgrader to reflect new rule directory path
This keeps BMAD Method files separate from existing project rules,
reducing chance of conflicts and improving organization.
Fixes#376
* chore: correct formatting in cursor rules directory path
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Co-authored-by: Stefan Klümpers <stefan.kluempers@materna.group>