klog/tty/pager: no more truncated lines — full lines flow, terminal wraps

- klog: MAX_LINE 128 -> 512 (lens widened u8 -> u16) — long serial_println
  lines (panics, boot messages) are no longer cut at 128 bytes; they
  print in full and the terminal wraps them at the screen edge
- tty: LINE_BUF_SIZE 256 -> 1024 — typed command lines longer than 256
  chars were silently dropped at the buffer limit; now they echo and
  submit in full (the terminal already wraps the echo mid-typing)
- pager (-p): screenfuls now count wrapped rows, not lines — a line
  wider than the terminal occupies ceil(len/cols) rows, so the pause
  lands at a real screen boundary instead of overflowing it

1 files changed, 4 insertions, 1 deletions

diff --git a/rsnix/src/tty.rs b/rsnix/src/tty.rs
index 81a7a24..7304925 100644
--- a/rsnix/src/tty.rs
+++ b/rsnix/src/tty.rs
@@ -17,7 +17,10 @@ use crate::ps2::{self, KeyEvent};
 use crate::strbuf;
 use crate::{gop, serial};
 
-pub const LINE_BUF_SIZE: usize = 256;
+/// Max characters a single typed line can hold.  Long enough that no
+/// realistic command line gets silently cut — the terminal wraps the
+/// echo at the screen edge, and the full line is what's submitted.
+pub const LINE_BUF_SIZE: usize = 1024;
 
 /// Result of one canonical line-input session.
 #[allow(clippy::large_enum_variant)] // stack buffer by design (no heap churn)