fix pi-lens warnings: unwraps, shell SC2046, dup code (fmtbuf/scripts/hexdump/cat/ahci/pci)

- memory.rs: self-test Layout::from_size_align no longer panics — the
  test fails cleanly on an invalid layout
- fat.rs: v() no longer unwraps the active-volume slot — invariant
  violation logs + halts instead of panicking mid-disk-io
- strbuf: shared FmtBuf replaces the duplicated PanicBuf/FmtBuf
  (main.rs + sched.rs)
- test-disk.sh: SC2046 — conditional --fresh arg no longer relies on
  word splitting
- scripts: boot.sh/boot-image.sh share lib-boot-args.sh (dup args loop)
- shell: cat/hexdump stdin pairs unified with Option<&str> marker;
  hexdump format_row folded into format_partial
- ahci: read/write_sectors unified behind dma_sectors
- pci: config_read/write share config_addr

1 files changed, 5 insertions, 16 deletions

diff --git a/rsdos/src/main.rs b/rsdos/src/main.rs
index 7ca031c..700dcc7 100644
--- a/rsdos/src/main.rs
+++ b/rsdos/src/main.rs
@@ -9,20 +9,9 @@ use rsnix::uefi::*;
 // Panic handler
 // ---------------------------------------------------------------------------
 
-/// Small fmt::Write over a byte slice (no allocation, bounded).
-struct PanicBuf<'a> {
-    b: &'a mut [u8],
-    n: usize,
-}
-
-impl core::fmt::Write for PanicBuf<'_> {
-    fn write_str(&mut self, s: &str) -> core::fmt::Result {
-        let m = s.len().min(self.b.len() - self.n);
-        self.b[self.n..self.n + m].copy_from_slice(&s.as_bytes()[..m]);
-        self.n += m;
-        Ok(())
-    }
-}
+// ---------------------------------------------------------------------------
+// Panic handler
+// ---------------------------------------------------------------------------
 
 #[panic_handler]
 fn panic(info: &PanicInfo) -> ! {
@@ -35,12 +24,12 @@ fn panic(info: &PanicInfo) -> ! {
     if rsnix::sched::is_ready() && !rsnix::sched::in_isr() && rsnix::sched::current() >= 2 {
         let mut buf = [0u8; 192];
         let n = {
-            let mut w = PanicBuf { b: &mut buf, n: 0 };
+            let mut w = rsnix::strbuf::FmtBuf::new(&mut buf);
             let _ = write!(&mut w, "{}", info.message());
             if let Some(loc) = info.location() {
                 let _ = write!(&mut w, " at {}:{}", loc.file(), loc.line());
             }
-            w.n
+            w.len()
         };
         let msg = core::str::from_utf8(&buf[..n]).unwrap_or("task panic");
         rsnix::sched::abort_current(msg);