Fix XAU/USD display name, pip value, and invalid symbol validation

- config.py: add XAU/USD and XAG/USD to SYMBOL_DISPLAY; add PIP_VALUES
  map for commodities (gold pip = $0.01, not $0.0001)
- data_provider.py: use PIP_VALUES in get_pair_info so gold trade setup
  shows correct pip counts instead of 269,000 pips for a $27 SL
- main.py: validate symbols in symbol_from_name — rejects non-alpha
  inputs like '15M' with a helpful hint to use --timeframe instead

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

main.py

@@ -380,11 +380,16 @@ Examples:
 
 
 def symbol_from_name(name: str) -> str:
-    """Convert pair name like 'EURUSD' to Yahoo symbol 'EURUSD=X'."""
-    name = name.upper().replace("/", "").replace("_", "")
-    if not name.endswith("=X"):
-        name += "=X"
-    return name
+    """
+    Convert pair name like 'EURUSD' or 'XAUUSD' to internal symbol 'EURUSD=X'.
+    Returns None for clearly invalid inputs (e.g. timeframe strings like '15M').
+    """
+    clean = name.upper().replace("/", "").replace("_", "").replace("=X", "")
+    if not clean.isalpha() or len(clean) < 5:
+        print(f"  Warning: '{name}' is not a valid pair symbol — skipping.")
+        print(f"  Hint: timeframes go in --timeframe (e.g. --timeframe M15), not --pairs.")
+        return None
+    return clean + "=X"
 
 
 def run_analysis(args) -> List[SignalReport]:
@@ -413,7 +418,11 @@ def run_analysis(args) -> List[SignalReport]:
 
     # Configure pairs
     if args.pairs:
-        config.watch_pairs = [symbol_from_name(p) for p in args.pairs]
+        symbols = [symbol_from_name(p) for p in args.pairs]
+        config.watch_pairs = [s for s in symbols if s is not None]
+        if not config.watch_pairs:
+            print("  Error: No valid pair symbols provided. Exiting.")
+            sys.exit(1)
     elif args.all:
         config.watch_pairs = MAJOR_PAIRS + CROSS_PAIRS
     else: