tool migration: v2 exports + 10 external CLI binaries

rsapi v2: 14 new ABI function pointers appended after v1 — fs_resolve,
fs_dir_next (iterator), fs_create, fs_remove, fs_read, fs_write,
fs_size, fs_close, rtc_now, mem_stats, pci_probe, pci_device,
klog_dump, kernel_version.  New C-repr structs: DirEntry, RtcTime,
MemStats, PciDevice, KernelVersion.  ABI_VERSION bumped to 2.

Shell-side: build_exports() constructs the full table at runtime per
invocation (replaces static const).  14 kernel-side wrapper functions
bridge rsapi types to rsnix kernel APIs; fs_dir_next maintains a
per-handle cache of children() results for iteration.

Tool binaries (10 crates, all linked against rsapi only):
- date: rtc_now → formatted YYYY-MM-DD HH:MM:SS
- mem: heap/pages free/total via mem_stats
- pci: pci_probe + pci_device enumerate all devices
- cat: fs_read paths or get_line stdin; put_line output
- ls: fs_resolve + fs_dir_next iteration; trailing / for dirs
- mkdir: fs_create(path, true)
- touch: fs_create(path, false)
- rm: fs_remove(path)
- klog: klog_dump 2048 bytes → put_line
- info: rtc_now + kernel_version (minimal; mem/pci deferred)

Gate verified: date prints RTC; pci lists all 4 QEMU devices
(8086:29c0, 1234:1111, 8086:10d3, 8086:2918); hello/boom/count
still work; test-disk PASS; poweroff clean.

1 files changed, 47 insertions, 0 deletions

diff --git a/bins/mem/src/main.rs b/bins/mem/src/main.rs
new file mode 100644
index 0000000..fd99f47
--- /dev/null
+++ b/bins/mem/src/main.rs
@@ -0,0 +1,47 @@
+//! mem — show memory statistics via the exports table.
+
+#![no_std]
+#![no_main]
+
+#[panic_handler]
+fn panic(_info: &core::panic::PanicInfo) -> ! {
+    loop { core::hint::spin_loop(); }
+}
+
+fn put(exports: &rsapi::Exports, buf: &[u8]) {
+    (exports.put_line)(rsapi::Line { ptr: buf.as_ptr(), len: buf.len() });
+}
+
+fn fmt_kib(exports: &rsapi::Exports, v: u64) {
+    let mut buf = [0u8; 32];
+    let kb = v / 1024;
+    let mut i = buf.len();
+    if kb == 0 { i -= 1; buf[i] = b'0'; }
+    else { let mut n = kb; while n > 0 { i -= 1; buf[i] = b'0' + (n % 10) as u8; n /= 10; } }
+    let s = b" KiB";
+    buf[i..i+s.len()].copy_from_slice(s);
+    put(exports, &buf[i..i+s.len()]);
+}
+
+#[unsafe(no_mangle)]
+pub extern "C" fn efi_main(exports: &'static rsapi::Exports, _argc: usize, _argv: *const rsapi::Arg) -> i32 {
+    let mut s = rsapi::MemStats { heap_total: 0, heap_free: 0, pages_total: 0, pages_free: 0 };
+    (exports.mem_stats)(&mut s);
+    let msg = b"heap:";
+    put(exports, msg);
+    put(exports, b"  free"); fmt_kib(exports, s.heap_free);
+    put(exports, b" / total"); fmt_kib(exports, s.heap_total);
+    let msg2 = b"pages:";
+    put(exports, msg2);
+    put(exports, b"  free");
+    let mut fb = [0u8; 16];
+    let mut i = fb.len();
+    let n = s.pages_free; if n==0 { i-=1; fb[i]=b'0'; } else { let mut m=n; while m>0 { i-=1; fb[i]=b'0'+(m%10) as u8; m/=10; } }
+    put(exports, &fb[i..]);
+    put(exports, b" / ");
+    let mut tb = [0u8; 16];
+    let mut j = tb.len();
+    let t = s.pages_total; if t==0 { j-=1; tb[j]=b'0'; } else { let mut m=t; while m>0 { j-=1; tb[j]=b'0'+(m%10) as u8; m/=10; } }
+    put(exports, &tb[j..]);
+    0
+}