feat(maea): migrate from MQL4 to MQL5 and simplify strategy

Migrate MAEA Expert Advisor from MetaTrader 4 to MetaTrader 5 platform with
significant strategy simplification and architectural improvements.

Key changes:
- Platform: MQL4 → MQL5
- Indicators: Reduced from 5 lines (3 EMAs + 2 borders) to 2 EMAs with zone fill
- Strategy: Removed pullback signals and dynamic lot sizing
- Lot sizing: Changed from dynamic (0.01/0.02) to fixed 0.01 lot
- Stop loss: Changed from Border Lines to opposite EMA (Buy: EMA Low, Sell: EMA High)
- Signal logic: Added opposite signal close for reversal protection
- New filter: Added minimum zone width filter (100 points)
- Documentation: Updated implementation plans and project summary
- New files: Added AGENTS.md, MAEA_Indicator.mq5, and opencode.jsonc

BREAKING CHANGE: Complete rewrite from MQL4 to MQL5 with simplified strategy.
Previous MAEA.mq4 and README.md deleted. New implementation requires MetaTrader 5.

opencode.jsonc

@@ -0,0 +1,13 @@
+{
+  "$schema": "https://opencode.ai/config.json",
+  "mcp": {
+    "mql5_help": {
+      "type": "local",
+      "command": [
+        "npx",
+        "-y",
+        "github:caoshuo594/mql5-help-mcp"
+      ]
+    }
+  }
+}