feat: improve CLI output and add verbose option

[ericanderson]

Summary

This PR implements comprehensive CLI output improvements as requested in issue #21. The main changes include:

• Centralized output management: New outputFormatter utility provides consistent output handling across all commands
• Verbose/quiet modes: Added -v/--verbose flag to all commands for detailed vs. essential output
• Improved default experience: Default mode now shows only essential information (results, summaries, errors)
• Better formatting: Consistent styling with emojis for success/warning/error messages and structured summaries

Changes Made

Core Infrastructure

• Added src/utils/outputFormatter.ts with centralized output functions
• Support for verbose/quiet modes with global state management
• Consistent formatting for sections, summaries, errors, and success messages

CLI Enhancement

• Added -v/--verbose flag to all three commands (remote, local, all)
• Output options are set per-command based on CLI flags
• Progress bars now only show in verbose mode

Output Improvements

• Default mode: Shows only essential information - final counts, summaries, and errors
• Verbose mode: Shows scanning progress, branch analysis details, progress bars, and detailed operation logs
• Improved error handling and messaging consistency
• Better formatting for interactive and non-interactive scenarios

Testing & Documentation

• Comprehensive unit tests for the new output formatter (20 test cases)
• Updated README with verbose flag usage examples and output mode explanations
• Added "Output Modes" section explaining when to use each mode

User Experience

Before (verbose by default)

Scanning for local branches that can be safely deleted...
Found 15 local branches
Fetching merged pull requests from GitHub...
Found 42 merged pull requests

Branch Analysis:
  Safe to delete: 3
  Unsafe to delete: 12
[progress bar with individual deletion messages]

After - Default mode (clean & concise)

Found 3 local branches that can be safely deleted.
Deleting 3 local branches:
  Deleted: feature-1 (#123)
  Deleted: feature-2 (#124)
  Deleted: feature-3 (#125)

Summary:
  Successfully deleted: 3 local branches
  Skipped (unsafe): 12

After - Verbose mode (detailed information)

Scanning for local branches that can be safely deleted...
Found 15 local branches
Fetching merged pull requests from GitHub...
Found 42 merged pull requests

Found 3 local branches that can be safely deleted.

Skipping 12 unsafe branches:
  - main (protected branch)
  - feature-wip (2 unpushed commits)
  [... detailed list]

Deleting 3 local branches:
[progress bar with real-time updates]
  Deleted: feature-1 (#123)
  [... etc]

Testing

• All new output formatter functionality has comprehensive unit tests
• Existing functionality preserved (some test updates needed for new output format)
• Manual testing confirms verbose/quiet modes work as expected across all commands

Documentation

• Updated README with verbose flag examples for all commands
• Added "Output Modes" section explaining usage scenarios
• All commands now show verbose flag in help output

Fixes #21

🤖 Generated with Claude Code

Co-Authored-By: Claude noreply@anthropic.com

[ericanderson]

should we just use winston or pino with a custom output formatter?