Introduces telegram_bot.py: python-telegram-bot v20+ async bot that
presents a persistent Scan Signal inline button. Each press fetches a
live USD/JPY signal via SignalAggregator and formats it with emoji,
MTF breakdown, top bull/bear reasons, and warnings. STRONG_BUY /
STRONG_SELL signals additionally render the full trade setup (entry,
SL, TP1, TP2, RR). Adds python-telegram-bot>=20.0 to requirements.txt.
Harwinder