chore: remove author attribution from TODO comments across multiple source files

Remove "(bob)" author prefix from all TODO comments in benchmark/method_call.wren, include/wren.h, src/main.c, src/wren_common.h, src/wren_compiler.c, src/wren_core.c, src/wren_value.c, src/wren_value.h, and src/wren_vm.c. Update the TODO_PATTERN regex in metrics script to match the new format without author parentheses. Also refactor test file counting in metrics to use os.walk with fnmatch for recursive directory traversal instead of glob.iglob.

test/closure/reuse_closure_slot.wren

@@ -14,6 +14,6 @@
   }
 }
 
-// TODO(bob): Closing over this.
-// TODO(bob): Close over fn/method parameter.
-// TODO(bob): Maximum number of closed-over variables (directly and/or indirect).
+// TODO: Closing over this.
+// TODO: Close over fn/method parameter.
+// TODO: Maximum number of closed-over variables (directly and/or indirect).

test/closure/use_global_in_function.wren

@@ -1,5 +1,5 @@
 var global = "global"
-// TODO(bob): Forward reference to global declared after use.
+// TODO: Forward reference to global declared after use.
 
 fn {
   io.write(global) // expect: global

test/closure/use_global_in_method.wren

@@ -1,5 +1,5 @@
 var global = "global"
-// TODO(bob): Forward reference to global declared after use.
+// TODO: Forward reference to global declared after use.
 
 class Foo {
   method {