feat: add range operators and iterator protocol for numeric for loops

Implement `..` and `...` infix operators on Num returning Range objects that support the iterator protocol, enabling concise numeric for loops like `for (i in 1..10)`. Add Range class with min/max properties and iterate/iteratorValue methods. Introduce TOKEN_DOTDOT and TOKEN_DOTDOTDOT lexer tokens with PREC_RANGE precedence in the compiler. Unroll method_call benchmark loops across all languages to stress dynamic dispatch instead of loop overhead, reducing iteration count from 1M to 100K with 10x unrolling. Update Wren benchmarks (binary_trees, fib, for) to use new range syntax. Add benchmark/README.md documenting each benchmark's purpose.

benchmark/method_call.wren

@@ -29,14 +29,21 @@ class NthToggle is Toggle {
 }
 
 var start = OS.clock
-var n = 1000000
-var i = 0
+var n = 100000
 var val = true
 var toggle = new Toggle(val)
 
-while (i < n) {
+for (i in 0...n) {
+  val = toggle.activate.value
+  val = toggle.activate.value
+  val = toggle.activate.value
+  val = toggle.activate.value
+  val = toggle.activate.value
+  val = toggle.activate.value
+  val = toggle.activate.value
+  val = toggle.activate.value
+  val = toggle.activate.value
   val = toggle.activate.value
-  i = i + 1
 }
 
 IO.write(toggle.value)
@@ -44,10 +51,17 @@ IO.write(toggle.value)
 val = true
 var ntoggle = new NthToggle(val, 3)
 
-i = 0
-while (i < n) {
+for (i in 0...n) {
+  val = ntoggle.activate.value
+  val = ntoggle.activate.value
+  val = ntoggle.activate.value
+  val = ntoggle.activate.value
+  val = ntoggle.activate.value
+  val = ntoggle.activate.value
+  val = ntoggle.activate.value
+  val = ntoggle.activate.value
+  val = ntoggle.activate.value
   val = ntoggle.activate.value
-  i = i + 1
 }
 
 IO.write(ntoggle.value)