feat: SL/TP risk formulas, project docs, symbol specs

SKILL.md Section 5 rewritten with PointValue-based formulas:
- Direction A: SL points → SL price
- Direction B: Risk% + lots → SL price (with currency conversion)
- Direction C: SL price + risk% → lot size
- FindFXRate helper for profit_currency ≠ account_currency
- OrderCalcProfit verification pattern

Section 8 expanded with 6 SL/TP pitfalls (PointValue vs TICK_VALUE,
TickSize ≠ Point, currency conversion, NormalizeDouble rounding,
lot step quantization, STOPS_LEVEL check).

Section 9 EA skeleton now includes inline PointValue, FindFXRate,
CalcSLFromRisk, CalcLotsFromSL functions.

New files:
- LICENSE (MIT)
- README.md
- docs-dev/symbol-spec.md (symbol spec workflow)
- skills/mql5/references/symbol-spec/specs-{XAUUSD,USDJPY}.csv
- skills/mql5/scripts/verify_sl_tp_formulas.py (Python verification)

Updated: pyproject.toml, AGENTS.md, .gitignore, docs-dev/skill-design.md

docs-dev/symbol-spec.md

@@ -0,0 +1,83 @@
+# Symbol Specification Workflow
+
+Broker-specific symbol specifications stored as CSV files, used by the
+SL/TP risk formula verification script.
+
+## Location
+
+```
+skills/mql5/references/symbol-spec/
+├── specs-XAUUSD.csv
+├── specs-USDJPY.csv
+└── ...
+```
+
+## CSV Format
+
+Each file is a two-column CSV (`Property,Value`) exported from the MT5
+Symbol Properties dialog. Key fields:
+
+| Field | Example (XAUUSD) | Example (USDJPY) | Used By |
+|-------|-------------------|-------------------|---------|
+| Digits | 2 | 3 | NormalizeDouble, Point |
+| Contract size | 100 | 100000 | PointValue, profit formula |
+| Calculation | CFD Leverage | Forex | Formula selection |
+| Tick size | 0.01 | 0.001 | Futures formula |
+| Tick value | 1.0 | 0.618839 | Futures formula |
+| Stops level | 0 | 0 | Min SL distance check |
+| Profit currency | USD | JPY | Currency conversion |
+| Minimal volume | 0.01 | 0.01 | Lot normalization |
+| Maximal volume | 80.00 | 80.00 | Lot normalization |
+| Volume step | 0.01 | 0.01 | Lot normalization |
+
+## How to Export from MT5
+
+1. In MT5: Tools → Symbols (or press Ctrl+U)
+2. Select the symbol → Properties tab
+3. Right-click → "Copy" or manually record values
+4. Create `specs-{SYMBOL}.csv` with the `Property,Value` format
+
+## How to Add a New Symbol
+
+1. Export specs from MT5 (see above)
+2. Save as `skills/mql5/references/symbol-spec/specs-{SYMBOL}.csv`
+3. Add the symbol to `verify_sl_tp_formulas.py`:
+   ```python
+   specs = {
+       "XAUUSD": SymbolSpec.from_csv(SPEC_DIR / "specs-XAUUSD.csv"),
+       "USDJPY": SymbolSpec.from_csv(SPEC_DIR / "specs-USDJPY.csv"),
+       "EURUSD": SymbolSpec.from_csv(SPEC_DIR / "specs-EURUSD.csv"),  # new
+   }
+   bids = {"XAUUSD": 4121.28, "USDJPY": 161.561, "EURUSD": 1.0850}
+   fx_rates = {"XAUUSD": 1.0, "USDJPY": 161.561, "EURUSD": 1.0}
+   ```
+4. Run `python skills/mql5/scripts/verify_sl_tp_formulas.py` to verify
+
+## Key Distinctions by Calc Mode
+
+### Forex (SYMBOL_CALC_MODE_FOREX)
+- Profit = `(close - open) × ContractSize × Lots`
+- PointValue = `point × ContractSize`
+- Example: USDJPY — ContractSize=100000, PointValue=100 JPY/pt/lot
+
+### CFD Leverage (SYMBOL_CALC_MODE_CFDLEVERAGE)
+- Profit = `(close - open) × ContractSize × Lots`
+- PointValue = `point × ContractSize`
+- Example: XAUUSD — ContractSize=100, PointValue=1.0 USD/pt/lot
+
+### Futures (SYMBOL_CALC_MODE_FUTURES)
+- Profit = `(close - open) × TickValue / TickSize × Lots`
+- PointValue = `point × TickValue / TickSize`
+- Uses broker-supplied TickValue instead of ContractSize
+
+## Currency Conversion
+
+When `SYMBOL_CURRENCY_PROFIT ≠ ACCOUNT_CURRENCY`:
+
+```
+risk_profcy = risk_account_cy × fx_rate
+```
+
+The verification script uses the `FindFXRate` helper to locate a Forex pair
+in Market Watch that converts between the two currencies. In MQL5 code,
+this is implemented in `SKILL.md` Section 5 (Direction B/C).