feat: post resting limit orders instead of only taking asks

[ten-nex]

Problem

All bots currently only take from the orderbook — they check for existing asks, and if there are none, they do nothing:

if not orderbook.asks:
    print(f'No asks available')
    return

This creates a deadlock: every bot waits for someone else to post first. The only liquidity comes from the MM, so every trade has the MM as counterparty. No bot-vs-bot crossing happens.

Solution

Change the default price_action_bot to post resting limit orders based on its price signal:

• Confidence → Price: Bot converts its signal confidence into a limit price (e.g., 60% confidence → bid at 58%, leaving 2% edge)
• Maker-first: If no matching ask exists, the order rests on the book for other bots to fill against
• Still takes when profitable: If there's an ask at or below the bot's price, it fills immediately (like before)
• 10-min expiry: Orders stay on the book for most of the market's life
• Signal management: Cancels stale orders on signal flip or HOLD, skips re-posting if already has a resting order

Impact

This is the structural fix for bot-vs-bot crossing. When multiple bots post resting orders with different views:

• Bot A posts YES bid at 58% (thinks BTC goes up)
• Bot B posts NO bid at 55% (thinks BTC goes down) → equivalent to YES ask at 45%
• They can cross each other — pure fee revenue, zero MM risk

The MM becomes a backstop, not the primary counterparty for every trade.