fix: multiple fixes to how REPL processes argv and autocomplete

[justinwilaby]

All items except W-18564386, W-18564784 and W-18564887 have been fixed in REPL & Prompt Mode Fixes for Releasable State

Overview

This PR introduces enhancements and refactoring to the CLI's interactive prompt and REPL (Read-Eval-Print Loop) experience. The changes focus on improving user input handling, command completion, and error management, as well as streamlining the main CLI entry point for better maintainability and user experience.

Key Features

• Improved interactive prompt logic for collecting and validating user input for commands, flags, and arguments.
• Enhanced REPL with better command completion, session state management, and history handling.
• Robust error handling and telemetry reporting for both normal and interrupted CLI sessions.
• The --repl flag was added to enter REPL mode.

Technical Details

• heroku-prompts.js now provides a more modular and robust set of prompt utilities, including support for required/optional inputs, file path validation, and boolean/choice prompts.
• The promptUser function is exported and used in the main CLI entry to collect user input interactively before command execution.
• heroku-repl.js introduces a class-based REPL with improved command completion (including dynamic completions for flags/args), persistent session state, and command history.

Testing Instructions

Prerequisites:

• Node.js and npm installed. Node v20+ required.
• All dependencies installed (yarn install).
• Build the CLI if required by your setup.

Test Scenarios:

1. REPL Launch: Run the CLI with the --repl flag (./bin/run --repl). Verify the REPL starts, supports command history, and provides completions for commands, flags, and arguments.
2. Prompted Command Execution: Run a CLI command with the --prompt flag (e.g., heroku apps:create --prompt). Verify that prompts appear for all required/optional inputs, including file paths and choices.
3. Verify fixes for all GUS items in this epic except the items specified above.

Impact

• Provides a more user-friendly and robust interactive CLI experience.
• Reduces user error by validating input and guiding users through required/optional parameters.
• Improves maintainability and extensibility of the CLI codebase.
• Enhances business value by making the CLI more approachable for new and existing users, reducing support burden.

[sbosio]

I will leave a list of further improvements but I'm not sure if they should be blockers or not, I suggest discussing these with Product:

• For W-18564266, the completion works for both short and long options, but also accepts short options with two dashes (that will eventually fail). Also by typing two consecutive dashes and pressing tab to autocomplete will insert argument placeholders before trying to complete option flag names. Finally, autocomplete will only work with a space between the flag name and value, but not with '=' that should be also accepted.
• For W-18564575 now the Redis CLI mode works, but it doesn't accepts short option flags.
• For W-18564625, REPL still shows "undefined" is not a valid command for empty lines.
• For W-18564625 now the run command executes. It doesn't accept short option flags and exits REPL mode when the command finalizes.
• For W-18574361, at least when testing with the sudo (legacy) plugin: The REPL mode is maintained if the command succeeds, but it's exited if the command fails. I don't know if this effects only legacy or all plugins.