feat(rust): Implement Rust-for-SUB-OS kernel layer, ChaCha20 crypto, HWMON thermal governor, and lazybox applets

- Add freestanding no_std Rust kernel layer compiled with rustc
- Implement memory-safe ChaCha20 RFC-8439 stream cipher and CSPRNG in Rust
- Implement intelligent thermal fan speed governor in Rust
- Add printk macro bridge (kprint!, kprintln!) for Rust
- Register 'rustinfo' and 'chacha20' LazyBox applets
- Enable x86_64 hardware FPU & SSE (CR4.OSFXSR/OSXMMEXCPT)
- Add cross-architecture C-bridge for ARM targets
- Update stage2.asm kernel sector copy bounds to 448 KB

kernel/main.c

@@ -58,6 +58,7 @@
 #include <net/tcp.h>
 #include <net/dhcp.h>
 #include <net/dns.h>
+#include <kernel/rust.h>
 #include <net/filter.h>
 #include <net/http.h>
 #include <net/ssh.h>
@@ -140,8 +141,9 @@ static void subos_modular_core_boot(void) {
     printk(ANSI_BRIGHT_GREEN "OK\n" ANSI_RESET);
 #endif
 
-    // Crypto, Certificates, LSM Security, Authentication & Namespaces
-    printk(KERN_INFO "[8/14] Initializing X.509 Keyring, Shadow Auth & Namespaces... ");
+    // Crypto, Certificates, LSM Security, Authentication, Namespaces & Rust Subsystem
+    printk(KERN_INFO "[8/14] Initializing Rust Core, X.509 Keyring, Shadow Auth & Namespaces... ");
+    rust_kernel_init();
     prng_seed(0, 0);
     certs_init();
     security_init();