Refactor CLI internals and polish terminal UX

[primaprashant]

• Replace hand-rolled timer/worker threads with rich Live displays
• Fix piped output: transcription is written raw to stdout, no wrapping or markup
• Record to a temp file so a cancelled recording no longer clobbers --last audio
• Clean error handling: proper exception chaining, clean Ctrl+C (exit 130), no tracebacks
• Add --model, --version, --no-copy, and -q/--quiet; remove --sample-rate and --channels
• Replace emoji status with plain glyphs and collapse per-run output to a single summary line
• Distinguish model download (first run) from model load in status messages
• Send --list-models names to stdout, hints to stderr