fix(ton-trading-bot): restore simulation balance on trade close (issue #96)

[konard]

Problem

The simulation balance in `ton_trading_simulate_trade` is decremented when a trade is opened (`amount_in` is subtracted from the virtual balance), but was never incremented when the trade was closed via `ton_trading_record_trade`. This caused the virtual balance to drain to zero regardless of trading performance.

Root cause: The credit-back guard in `ton_trading_record_trade` checked `entry.to_asset === "TON"`, which only matched TON→TON round-trips. For the common case of TON→USDT trades, `to_asset` is USDT so the credit was silently skipped.

Fix

Changed the guard from `entry.to_asset === "TON"` to `entry.from_asset === "TON"` (TON was what was deducted at open) and updated the credit calculation to return principal + PnL in TON:

• When USD prices are available: `credit_ton = amount_in + pnl_usd / entry_price_usd`
• When no prices are stored (same-currency TON→TON trade): `credit_ton = amount_out` (same behaviour as before)

New tools (feature requests from issue)

• `ton_trading_reset_simulation_balance` — reset the virtual balance to a starting amount (defaults to `pluginConfig.simulationBalance`) for a fresh paper-trading session
• `ton_trading_set_simulation_balance` — manually set the virtual balance to any amount to align with a real portfolio

How to reproduce the bug (before fix)

```

1. Start with balance = 1000 TON
2. simulate_trade(from_asset="TON", to_asset="USDT_ADDR", amount_in=100, ...) → balance 900
3. record_trade(trade_id=1, amount_out=105, exit_price_usd=1) → balance stays 900 (bug)
4. Expected: balance ≈ 1000 + pnl_ton
   ```

Tests

4 new regression tests for the balance credit-back fix:

• credits principal + profit (TON→USDT with USD prices)
• credits `amount_out` directly for same-currency TON→TON trades
• does NOT credit for non-TON from_asset trades (USDT→TON)
• correctly handles losing trades (principal - loss in TON)

4 new tests for the two new tools.

All 104 tests pass locally (`node --test plugins/ton-trading-bot/tests/index.test.js`).

Fixes #96

[konard]

🤖 Solution Draft Log

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💰 Cost estimation:

• Public pricing estimate: $1.336784
• Calculated by Anthropic: $1.336784 USD
• Difference: $0.000000 (0.00%)

📊 Context and tokens usage:

Claude Sonnet 4.6:

• Max context window: 79.2K / 1M input tokens (8%)
• Max output tokens: 16.0K / 64K output tokens (25%)

Total input tokens: 69.2K + 2.3M cached
Total output tokens: 16.0K output
Cost: $1.174467

Claude Haiku 4.5:

• Context window: 542.9K / 200K tokens (271%)
• Max output tokens: 5.3K / 64K output tokens (8%)

Total input tokens: 70.8K + 472.2K cached
Total output tokens: 5.3K output
Cost: $0.162317

🤖 Models used:

• Tool: Anthropic Claude Code
• Requested: sonnet
• Main model: Claude Sonnet 4.6 (claude-sonnet-4-6)
• Additional models:
  • Claude Haiku 4.5 (claude-haiku-4-5-20251001)

📎 Log file uploaded as Gist (1488KB)

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[konard]

✅ Ready to merge

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