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.
Add DEF_PRIMITIVE(list_removeAt) to src/primitives.c that removes an element at a given index from an ObjList, shifts remaining elements up, shrinks capacity when excess is detected via LIST_GROW_FACTOR, and returns the removed Value. Register the primitive as "removeAt " on vm->listClass. Create test/list/remove_at.wren covering removal at positive indices 0,1,2, negative indices -1,-2,-3, out-of-bounds cases returning null, and verification that the removed value is returned.
