Infrastructure: Issue templates for contribution types

[PetarStoev02]

Parent

Part of w3-kit/cli#4 (Phase 5: Scale + Community)

Goal

Create GitHub issue templates for each contribution type.

Templates needed

• New recipe submission
• New UI component submission
• New guide/cheat sheet submission
• Bug report
• Feature request
• Documentation improvement

Requirements

• YAML-based issue forms (.github/ISSUE_TEMPLATE/)
• Auto-labeling per template
• Clear checklists for contributors