v0.1.2: Prompt to install missing dependencies

Features

• agentic setup, agentic doctor, and install.sh now prompt to install missing dependencies
  • If claude CLI or optional clauder is not found and stdin is a TTY, offer to run the install command with interactive y/N prompt
  • Non-interactive contexts (piped stdin, CI/sandbox) gracefully degrade to printing the install command for manual installation
  • install.sh also checks for curl early and recommends platform-specific install help if missing

Implementation

• New cmd/deps.go: shared promptInstall() helper for interactive y/N prompts with TTY detection
• install.sh uses /dev/tty to read prompts even when stdin is piped (crucial for curl | sh workflows), with safe fallback for sandboxes/CI without controlling terminal
• Promoted github.com/mattn/go-isatty to direct dependency

Testing

All paths verified:

• Interactive prompts (user accepts/declines)
• Non-TTY stdin (piped from other commands, redirected from files)
• No controlling terminal (edge case in some CI/sandbox setups)