Retry / replay commands, output to file, shell completions

[kristoferlund]

Added

• Output mode configuration - Control transcription output destination with CLI flags:
  • Default: outputs to stdout for piping to other commands
  • -c flag: copy to clipboard
  • -o <file> flag: write to file
• Retry command - Re-transcribe previous recordings without re-recording audio (ostt retry or ostt retry N)
• Replay command - Playback previous recordings using system audio player (ostt replay or ostt replay N)
• Recording history - Maintains history of 10 most recent audio recordings with automatic rotation
• Command aliases - Short aliases for common commands: r (record), a (auth), h (history), k (keywords), c (config), rp (replay)
• Rich help system - Two-tier help with -h (short) and --help (long with examples)
• Improved error messages - Typo suggestions and better command-not-found errors
• Shell completions - Generate completion scripts for bash, zsh, fish, and PowerShell (ostt completions <shell>)

Changed

• CLI framework migration - Migrated from manual argument parsing to clap for better UX and maintainability
• ostt record now outputs to stdout by default (enables shell piping) instead of clipboard
• BREAKING CHANGE for Hyprland/macOS popup users: Default output changed to stdout. Update your integration scripts to add -c flag for clipboard output. See upgrade guides:
  • Hyprland Upgrade Guide
  • macOS Upgrade Guide

Fixed

• Transcribed text no longer includes leading/trailing whitespace added by transcription models

Closes #14
Closes #15
Closes #17
Closes #18
Closes #20