core: add interactive question tool for gathering user preferences and clarifying instructions

[thdxr]

Summary

• Add interactive question tool for gathering user preferences and clarifying instructions
• Enables opencode to ask users questions during execution to:
  • Gather user preferences or requirements
  • Clarify ambiguous instructions
  • Get decisions on implementation choices
  • Offer choices to users about direction to take

Changes

• New question tool added to the toolset
• Supports multiple choice questions with optional descriptions
• Users can always select "Other" for custom text input
• Recommended options can be marked with "(Recommended)" suffix