fix: correct bot status pnl percentage

[fudujiji]

Summary

• format bot status global_pnl_pct values without applying an extra x100 multiplier
• keep the shared decimal percentage formatter unchanged for other formatter paths

Fixes #16.

Verification

• .venv/bin/python -m ruff check hummingbot_mcp/formatters/bots.py
• .venv/bin/python -m compileall -q hummingbot_mcp
• manual formatter check with global_pnl_pct=-0.3291 renders -0.33%, not -32.91%