Add explicit include for uintptr_t in StringMacros.cc

[Copilot]

Addresses feedback from PR #320 to add proper header declaration for uintptr_t type used in address math helper functions.

Changes

• Added #include <cstdint> to otsdaq/Macros/StringMacros.cc to explicitly declare uintptr_t instead of relying on transitive includes

The type is used in find_library_base() and resolve_stack_entry() for pointer arithmetic when resolving stack traces:

#include "otsdaq/Macros/StringMacros.h"

#include <algorithm>  // for find_if
#include <array>
#include <cstdint>    // for uintptr_t

using namespace ots;

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