feat: implement initial CPIO parsing and shell improvements

- core: added CPIO parser (fs/cpio.c) and VFS structs

- shell: refactored ksh, added 'help' command

- lib: added string utils (strcpy, strncpy, strncmp)

- wip: working on initramfs loading in kmain

common/bootinfo.h

@@ -7,7 +7,7 @@ typedef unsigned int       bi_u32;
 typedef unsigned long long bi_u64; 
 
 typedef struct {
-    bi_u32 *base;
+    bi_u32* base;
     bi_u64 base_size;
     bi_u64 width;
     bi_u64 height;
@@ -15,7 +15,7 @@ typedef struct {
 } BI_Framebuffer;
 
 typedef struct {
-    void *map;             
+    void* map;             
     bi_u64 map_size;       
     bi_u64 descriptor_size;
     bi_u32 map_key;
@@ -23,6 +23,15 @@ typedef struct {
 } BI_MemoryMap;
 
 typedef struct {
+    void* addr;
+    bi_u64 size;
+} BI_Initramfs;
+
+typedef struct {
+    bi_u64 magic;
     BI_Framebuffer framebuffer;
     BI_MemoryMap mem;
-} Bootinfo;
+    BI_Initramfs initramfs;
+} Bootinfo;
+
+#define BOOTINFO_MAGIC 0x7E833055 // termOS