fix: Add missing ByteUtilities.h include and use coroStackSize constant

- Include ByteUtilities.h in Coro.ipp so megabytes() is declared
- Use coroStackSize constant in coroutine constructor instead of
  hardcoded 1536*1024, enabling sanitizer-aware stack sizing
- Initialize local variable in PropertyStream destructor to satisfy
  clang-tidy cppcoreguidelines-init-variables

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

include/xrpl/core/Coro.ipp

@@ -1,5 +1,7 @@
 #pragma once
 
+#include <xrpl/basics/ByteUtilities.h>
+
 #include <cstddef>
 
 namespace xrpl {
@@ -25,9 +27,7 @@ JobQueue::Coro::Coro(Coro_create_t, JobQueue& jq, JobType type, std::string cons
     , name_(name)
     , running_(false)
     , coro_(
-          // Stack size of 1MB wasn't sufficient for deep calls. ASAN tests flagged the issue. Hence
-          // increasing the size to 1.5MB.
-          boost::context::protected_fixedsize_stack(1536 * 1024),
+          boost::context::protected_fixedsize_stack(coroStackSize),
           [this, fn = std::forward<F>(f)](
               boost::coroutines2::asymmetric_coroutine<void>::push_type& do_yield) {
               yield_ = &do_yield;

src/libxrpl/beast/utility/beast_PropertyStream.cpp

@@ -161,7 +161,7 @@ PropertyStream::Source::~Source()
     // Read parent_ under lock, then release before calling remove()
     // to maintain consistent lock ordering (parent before child),
     // matching the order used in find_one_deep().
-    Source* parent;
+    Source* parent = nullptr;
     {
         std::lock_guard _(lock_);
         parent = parent_;