feat: implement scientific notation parsing for number literals in wren compiler

Add support for parsing scientific notation (e.g., 2.55e2, -2.55e-2) in the
readNumber function of wren_compiler.c. The implementation handles optional
negative exponents, validates that exponent digits follow 'e'/'E', and emits
a lex error for unterminated scientific notation. Also adds comprehensive
test cases covering valid scientific literals, missing exponents, floating
exponents, missing fractional parts, and multiple exponents.

src/vm/wren_compiler.c

@@ -608,7 +608,6 @@ static void readHexNumber(Parser* parser)
 // Finishes lexing a number literal.
 static void readNumber(Parser* parser)
 {
-  // TODO: scientific, etc.
   while (isDigit(peekChar(parser))) nextChar(parser);
 
   // See if it has a floating point. Make sure there is a digit after the "."
@@ -618,6 +617,22 @@ static void readNumber(Parser* parser)
     nextChar(parser);
     while (isDigit(peekChar(parser))) nextChar(parser);
   }
+  
+  // See if the number is in scientific notation
+  if (peekChar(parser) == 'e' || peekChar(parser) == 'E')
+  {
+    nextChar(parser);
+    
+    // if the exponant is negative
+    if(peekChar(parser) == '-') nextChar(parser);
+    
+    if(!isDigit(peekChar(parser)))
+    {
+      lexError(parser, "Unterminated scientific notation.");
+    }
+    
+    while (isDigit(peekChar(parser))) nextChar(parser);
+  }
 
   makeNumber(parser, false);
 }