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, 17 insertions, 0 deletions

diff --git a/bins/touch/src/main.rs b/bins/touch/src/main.rs
new file mode 100644
index 0000000..5cd61e3
--- /dev/null
+++ b/bins/touch/src/main.rs
@@ -0,0 +1,17 @@
+//! touch — create an empty file via the exports table.
+
+#![no_std]
+#![no_main]
+
+#[panic_handler]
+fn panic(_info: &core::panic::PanicInfo) -> ! {
+    loop { core::hint::spin_loop(); }
+}
+
+#[unsafe(no_mangle)]
+pub extern "C" fn efi_main(exports: &'static rsapi::Exports, argc: usize, argv: *const rsapi::Arg) -> i32 {
+    let args = unsafe { core::slice::from_raw_parts(argv, argc) };
+    if args.is_empty() { return 1; }
+    let path = unsafe { core::str::from_utf8_unchecked(core::slice::from_raw_parts(args[0].ptr, args[0].len)) };
+    (exports.fs_create)(rsapi::Line { ptr: path.as_ptr(), len: path.len() }, false)
+}