feat: add 5 dashboard features — dark mode, trade history, backtests, model insights, alerts

- Dark mode: class-based theme toggle with localStorage persistence and flash prevention
- Trade History (/trades): paginated table, stats cards, equity curve chart with DB API endpoints
- Backtest Viewer (/backtests): log parser for 35 backtest results, sidebar + detail + comparison tabs
- Model Insights: dashboard card + dialog showing feature importance, regime distribution, training history
- Alert/Signal Log (/alerts): signal stats, filterable table with execution tracking
- API: 8 new endpoints with psycopg2 DB connection pool
- Dark mode sweep across books page, about dialog, and all dashboard components
- Architecture docs rewritten with Mermaid diagrams (23 docs)
- README and FEATURES.md rewritten bilingual (Indonesian + English)
- main_live.py: write model_metrics.json on startup and retrain

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

web-dashboard/api/db.py

@@ -0,0 +1,97 @@
+"""
+Database connection pool for Trading Bot API.
+Uses psycopg2 with a simple connection pool.
+"""
+
+import os
+import logging
+from contextlib import contextmanager
+from typing import Optional
+
+import psycopg2
+from psycopg2 import pool
+from psycopg2.extras import RealDictCursor
+
+logger = logging.getLogger(__name__)
+
+_pool: Optional[pool.SimpleConnectionPool] = None
+
+
+def get_db_config() -> dict:
+    return {
+        "host": os.getenv("DB_HOST", "localhost"),
+        "port": int(os.getenv("DB_PORT", "5432")),
+        "dbname": os.getenv("DB_NAME", "trading_db"),
+        "user": os.getenv("DB_USER", "trading_bot"),
+        "password": os.getenv("DB_PASSWORD", "trading_bot_2026"),
+    }
+
+
+def init_pool(minconn: int = 1, maxconn: int = 5):
+    """Initialize connection pool."""
+    global _pool
+    if _pool is not None:
+        return
+    try:
+        config = get_db_config()
+        _pool = pool.SimpleConnectionPool(minconn, maxconn, **config)
+        logger.info("Database pool initialized: %s@%s:%s/%s", config["user"], config["host"], config["port"], config["dbname"])
+    except Exception as e:
+        logger.warning("Could not initialize DB pool: %s", e)
+        _pool = None
+
+
+def close_pool():
+    """Close all pool connections."""
+    global _pool
+    if _pool:
+        _pool.closeall()
+        _pool = None
+        logger.info("Database pool closed")
+
+
+@contextmanager
+def get_conn():
+    """Get a connection from the pool (context manager)."""
+    if _pool is None:
+        raise RuntimeError("Database pool not initialized")
+    conn = _pool.getconn()
+    try:
+        yield conn
+    finally:
+        _pool.putconn(conn)
+
+
+@contextmanager
+def get_cursor(commit: bool = False):
+    """Get a dict cursor from the pool."""
+    with get_conn() as conn:
+        cursor = conn.cursor(cursor_factory=RealDictCursor)
+        try:
+            yield cursor
+            if commit:
+                conn.commit()
+        except Exception:
+            conn.rollback()
+            raise
+        finally:
+            cursor.close()
+
+
+def query(sql: str, params: tuple = (), one: bool = False):
+    """Execute a query and return results as list of dicts."""
+    try:
+        with get_cursor() as cur:
+            cur.execute(sql, params)
+            rows = cur.fetchall()
+            if one:
+                return dict(rows[0]) if rows else None
+            return [dict(r) for r in rows]
+    except Exception as e:
+        logger.error("DB query error: %s", e)
+        return None if one else []
+
+
+def is_available() -> bool:
+    """Check if DB is available."""
+    return _pool is not None