[AdamMagued]

When progress bars within a Pool have CleanOnFinish enabled, finishing individual bars or stopping the pool leaves trailing bar lines during pool redraw cycles because Pool.print does not account for CleanOnFinish and unconditionally renders all bars.

Changes

• In Pool.print:
  • Identify and filter out completed bars that have CleanOnFinish enabled.
  • Overwrite lines left by cleared bars with spaces when the active bar count decreases.
  • Reposition the cursor back to the bottom of the remaining active bars.
  • Prune finished CleanOnFinish bars from p.bars to avoid unbounded slice growth and ensure terminal height truncation operates on visible bars.
  • Avoid emitting cursor-up escape sequences when lastBarsCount is 0.
• Update Pool.writer to ensure first is updated on the initial tick.
• Add regression test suite in v3/pool_test.go verifying single-bar and multi-bar pool cleanups, redraw cycle line clearing, cursor repositioning, and concurrent worker updates.

Fixes #223.

[AdamMagued]

Closing in favor of maintainer PR #249 to keep the review queue clean.