Evaluate CLI libraries and choose one

[SorraTheOrc]

Compare candidate CLI libraries (oclif, yargs, commander, cac, ink) and pick the best fit for ToneForge. Include migration approach and rough effort estimate.\n\nRepo notes:\n- Current top-level entry is which loads via tsx and exports for tests.\n- Tests import (compiled) in many files; preserve signature to avoid large test changes.\n\nAcceptance criteria:\n- Documented pros/cons for each candidate\n- Recommendation of a single library with rationale\n- Migration plan with required code changes and risk notes\n- Rough effort estimate (low/medium/high and hours)\n

[SorraTheOrc]

\n\n**OpenCode**\n\nCreated child task TF-0MMJ8H4QF0YDO4WX and added evaluation doc at docs/cli-library-evaluation.md. Recommended with migration plan and estimates. Will implement POC wiring in the next task.

[SorraTheOrc]

\n\n**OpenCode**\n\nDecision recorded: yargs selected and minimal yargs wrapper added (src/cli.yargs.ts). Marking evaluation as plan_complete and proceeding with incremental implementation under yargs.