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, 38 insertions, 0 deletions

diff --git a/bins/date/src/main.rs b/bins/date/src/main.rs
new file mode 100644
index 0000000..880833e
--- /dev/null
+++ b/bins/date/src/main.rs
@@ -0,0 +1,38 @@
+//! date — show current RTC time 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 dig(b: u8) -> [u8; 2] { [b'0' + b / 10, b'0' + b % 10] }
+
+#[unsafe(no_mangle)]
+pub extern "C" fn efi_main(exports: &'static rsapi::Exports, _argc: usize, _argv: *const rsapi::Arg) -> i32 {
+    let mut t = rsapi::RtcTime { year: 0, month: 0, day: 0, hour: 0, minute: 0, second: 0, _pad: 0 };
+    (exports.rtc_now)(&mut t);
+    // "YYYY-MM-DD HH:MM:SS" = 19 bytes
+    let mut buf = [0u8; 19];
+    let y = t.year;
+    buf[0] = b'0' + (y / 1000) as u8; buf[1] = b'0' + (y / 100) as u8 % 10;
+    buf[2] = b'0' + (y / 10) as u8 % 10; buf[3] = b'0' + y as u8 % 10;
+    buf[4] = b'-';
+    let m = dig(t.month); buf[5] = m[0]; buf[6] = m[1];
+    buf[7] = b'-';
+    let d = dig(t.day); buf[8] = d[0]; buf[9] = d[1];
+    buf[10] = b' ';
+    let h = dig(t.hour); buf[11] = h[0]; buf[12] = h[1];
+    buf[13] = b':';
+    let mi = dig(t.minute); buf[14] = mi[0]; buf[15] = mi[1];
+    buf[16] = b':';
+    let s = dig(t.second); buf[17] = s[0]; buf[18] = s[1];
+    put(exports, &buf);
+    0
+}