feat: add kernel ACPI support for querying battery percentage, add battery indicator to desktop, move log state to 0:/state directory

kernel/src/Memory/Paging.hpp

@@ -90,6 +90,14 @@ public:
         Paging();
         void Init(std::uint64_t kernelBaseVirt, std::uint64_t kernelSize, const montauk::boot::MemoryMap& memMap,
                   const montauk::boot::Framebuffer& framebuffer);
+        // Top of the contiguous HHDM mapping built by Init(). A physical
+        // address at or above this is NOT reachable at phys+hhdmBase, and
+        // dereferencing it there faults (non-canonical addresses raise #GP
+        // rather than #PF). Anything that turns firmware-supplied numbers into
+        // HHDM pointers -- the AML interpreter's SystemMemory regions above all
+        // -- must check against this first.
+        static std::uint64_t HhdmLimit();
+
         void Map(std::uint64_t physicalAddress, std::uint64_t virtualAddress);
         void MapMMIO(std::uint64_t physicalAddress, std::uint64_t virtualAddress);
         void MapWC(std::uint64_t physicalAddress, std::uint64_t virtualAddress);