refactor: drop poll_for_swap_creation, reuse poll_for_swap_with_progress in post-tx

[dataCenter430]

Closes: #137

Summary

poll_for_swap_creation in swap.py was a duplicate of poll_for_swap_with_progress — identical polling logic, but with a static spinner and no elapsed-time feedback.
It had a single call site in post_tx.py.

Changes:

• Add a message parameter to poll_for_swap_with_progress (default keeps existing callers unchanged)
• Replace the poll_for_swap_creation call in post_tx.py with poll_for_swap_with_progress,
  passing message='Waiting for swap to appear on-chain...' to preserve the original UX text
• Delete poll_for_swap_creation from swap.py

Visual diff (alw swap post-tx final polling step)

Before:

⠋ Waiting for swap to appear on-chain...

(static — no time feedback)

After:

⠋ Waiting for swap to appear on-chain... 0:00 elapsed
⠙ Waiting for swap to appear on-chain... 0:03 elapsed
⠹ Waiting for swap to appear on-chain... 0:06 elapsed

(same message, now with live elapsed time, keep clean and concise code, remove unnecessary duplication)

[dataCenter430]

Hi, @LandynDev
Would be it possible to review the PR? 🙏
Thanks

[dataCenter430]

Hi, @LandynDev
Could you please review the PR?