feat(rumpk): Sovereign Core enhancements - NexShell IPC hardening & NipBox utility expansion

- Improved NexShell signal integrity by consolidating ION packet transmission.
- Added 'ls' and enhanced 'matrix' control to NipBox (Sovereign Coreutils).
- Added emergency matrix override to NexShell kernel mode.
- Fixed 'command not found' errors caused by IPC fragmentation.

npl/nipbox/nipbox.nim

@@ -0,0 +1,89 @@
+# src/npl/nipbox/nipbox.nim
+import std/[strutils, tables]
+
+# --- COMMANDS ---
+
+proc do_echo(args: seq[string]) =
+  echo args.join(" ")
+
+proc do_ls(args: seq[string]) =
+  # A Sovereign 'ls' - eventually this will query the NPL filesystem
+  echo ".          .."
+  echo "kernel     subject"
+  echo "matrix     ion"
+  echo "vault      pki"
+
+const CMD_GPU_MATRIX = 0x100
+const CMD_GPU_CLEAR = 0x101
+
+proc nexus_syscall(cmd: uint32, arg: uint32): cint {.importc, cdecl.}
+
+proc do_matrix(args: seq[string]) =
+  let enable = if args.len > 0 and args[0] == "off": 0'u32 else: 1'u32
+  let state = if enable == 1: "ON" else: "OFF"
+  echo "[NipBox] Matrix Protocol: Setting state to " & state
+  if nexus_syscall(CMD_GPU_MATRIX, enable) != 0:
+    echo "[Error] Command Ring Full!"
+  else:
+    echo "[NipBox] Command Sent Successfully."
+
+proc do_help(args: seq[string]) =
+  echo "NipBox v0.1 (Sovereign Coreutils)"
+  echo "  echo [args...] : Print arguments"
+  echo "  ls             : List sovereign objects"
+  echo "  matrix [on/off]: Toggle visualizer"
+  echo "  help           : Show this message"
+  echo "  version        : Show version info"
+
+proc do_version(args: seq[string]) =
+  echo "NipBox v0.1.0"
+  echo "Built: 2025-12-31"
+  echo "Architect: Markus Maiwald | Voxis Forge (AI)"
+
+const CMD_GET_GPU_STATUS = 0x102
+
+proc do_status(args: seq[string]) =
+  echo "[NipBox] Querying GPU Status..."
+  let status = nexus_syscall(CMD_GET_GPU_STATUS, 0)
+  echo "GPU Status: ", if status == 1: "ONLINE (Retina Active)" else: "OFFLINE"
+
+# --- DISPATCHER ---
+
+const commands = {
+  "echo": do_echo,
+  "ls": do_ls,
+  "matrix": do_matrix,
+  "status": do_status,
+  "help": do_help,
+  "version": do_version
+}.toTable
+
+proc main() =
+  proc nexus_yield() {.importc, cdecl.}
+  echo "\n[NipBox] Shell Ready. Waiting for orders..."
+
+  while true:
+    stdout.write("root@nexus:# ")
+    stdout.flushFile()
+
+    let line = try: stdin.readLine() except: ""
+
+    if line.len == 0:
+      nexus_yield()
+      continue
+
+    let parts = line.split(' ')
+    if parts.len == 0: continue
+    let cmd = parts[0]
+    let args = if parts.len > 1: parts[1..^1] else: @[]
+
+    if commands.hasKey(cmd):
+      commands[cmd](args)
+    elif cmd == "exit":
+      echo "[NipBox] Dropping to Kernel View..."
+      break
+    else:
+      echo "nipbox: command not found: ", cmd
+
+when isMainModule:
+  main()

src/npl/system/nexshell.zig

@@ -1,8 +1,7 @@
-const std = @import("std");
-
 // NEXUS IMMUNE SYSTEM (NPL) - THE VOICE & COMMAND PLANE
 // Markus Maiwald (Architect) | Voxis Forge (AI)
 
+const std = @import("std");
 const ION_BASE = 0x83000000;
 
 const IonPacket = extern struct {
@@ -32,10 +31,13 @@ const SysTable = extern struct {
     s_tx: *RingBuffer(IonPacket),
     s_event: *RingBuffer(IonPacket),
     s_cmd: *RingBuffer(CmdPacket),
+    s_input: *RingBuffer(IonPacket),
 };
 
 const CMD_ION_STOP = 1;
 const CMD_ION_START = 2;
+const CMD_GPU_MATRIX = 0x100;
+const CMD_GET_GPU_STATUS = 0x102;
 
 // The Main Loop for the NexShell Fiber
 export fn nexshell_main() void {
@@ -93,19 +95,55 @@ export fn nexshell_main() void {
     }
 }
 
+var forward_mode: bool = true;
+
 fn process_command(cmd_text: []const u8, cmd_ring: *RingBuffer(CmdPacket)) void {
+    if (cmd_text.len == 0) return;
+
+    if (forward_mode) {
+        const is_toggle = std.mem.eql(u8, cmd_text, "kernel") or std.mem.eql(u8, cmd_text, "exit");
+
+        // ALWAYS FORWARD TO USERLAND first so it can process its own exit
+        print("[NexShell] Forwarding to Subject...\n");
+
+        // Combine command + newline to avoid fragmentation
+        if (cmd_text.len > 0) {
+            var forward_buf: [128]u8 = undefined;
+            const copy_len = if (cmd_text.len > 126) 126 else cmd_text.len;
+            @memcpy(forward_buf[0..copy_len], cmd_text[0..copy_len]);
+            forward_buf[copy_len] = '\n';
+            ion_push_stdin(forward_buf[0 .. copy_len + 1].ptr, copy_len + 1);
+        }
+
+        if (is_toggle) {
+            forward_mode = false;
+            print("[NexShell] Dropping to Kernel Debug Mode.\n");
+        }
+    } else {
+        if (std.mem.eql(u8, cmd_text, "subject") or std.mem.eql(u8, cmd_text, "nipbox")) {
+            forward_mode = true;
+            print("[NexShell] Resuming Subject Pipe.\n");
+            return;
+        }
+
         if (std.mem.eql(u8, cmd_text, "io stop") or std.mem.eql(u8, cmd_text, "ion stop")) {
             print("[NexShell] Pushing CMD_ION_STOP...\n");
             push_cmd(cmd_ring, CMD_ION_STOP, 0);
-    } else if (std.mem.eql(u8, cmd_text, "io start") or std.mem.eql(u8, cmd_text, "ion start")) {
-        print("[NexShell] Pushing CMD_ION_START...\n");
-        push_cmd(cmd_ring, CMD_ION_START, 0);
-    } else if (cmd_text.len > 0) {
-        print("[NexShell] Unknown Command: ");
+        } else if (std.mem.eql(u8, cmd_text, "matrix on")) {
+            print("[NexShell] Engaging Matrix Protocol (Emergency Override)...\n");
+            push_cmd(cmd_ring, CMD_GPU_MATRIX, 1);
+        } else if (std.mem.eql(u8, cmd_text, "matrix off")) {
+            print("[NexShell] Disengaging Matrix Protocol...\n");
+            push_cmd(cmd_ring, CMD_GPU_MATRIX, 0);
+        } else if (std.mem.eql(u8, cmd_text, "matrix status")) {} else if (std.mem.eql(u8, cmd_text, "help")) {
+            print("[NexShell] Kernel Commands: io stop, matrix on/off, matrix status, subject, help\n");
+        } else {
+            print("[NexShell] Unknown Kernel Command: ");
             print(cmd_text);
             print("\n");
         }
     }
+}
 
 fn push_cmd(ring: *RingBuffer(CmdPacket), kind: u32, arg: u32) void {
     const head = @atomicLoad(u32, &ring.head, .acquire);
@@ -124,6 +162,7 @@ fn push_cmd(ring: *RingBuffer(CmdPacket), kind: u32, arg: u32) void {
 // OS Shims
 extern fn write(fd: c_int, buf: [*]const u8, count: usize) isize;
 extern fn console_read() c_int;
+extern fn ion_push_stdin(ptr: [*]const u8, len: usize) void;
 extern fn fiber_yield() void;
 
 fn print(text: []const u8) void {