fix: remove extra blank lines in railway agent REPL output

[codyde]

Summary

• The railway agent interactive REPL was printing multiple blank lines between user input and the agent's response
• Root cause: both the thinking spinner setup and the Chunk/ToolCallReady handlers unconditionally emitted println!(), so each finish_and_clear (which already leaves the cursor on an empty line) was followed by another newline — stacking 2+ blank lines per turn, more when tool calls ran first
• Dropped the unconditional println!() before the initial spinner in both run_single_shot and run_repl, and made the println!() inside the Chunk and ToolCallReady handlers conditional on whether a spinner was just cleared

Before

> You: Yes confirmed




Railway Agent: Done. All 3 services have been marked for removal:

After

> You: Yes confirmed
Railway Agent: Done. All 3 services have been marked for removal:

Test plan

• cargo check passes
• Run railway agent and confirm no extra blank lines between > You: and Railway Agent:
• Confirm tool-call spinners still render correctly and don't get overwritten by subsequent output
• Confirm single-shot mode (railway agent -p "...") still renders cleanly

🤖 Generated with Claude Code