tty: the grid was 80x24 on a 160x50 screen, and wrapping was eager

Three symptoms, two causes, both in the terminal layer.

**The grid and TIOCGWINSZ disagreed about the size.** vt_init() sizes every
grid from gfx_cols()/gfx_rows(), and it runs at main.c:75 -- while the display
driver attaches its scanout from the PCI bus walk at main.c:99. So the grids
were the 80x24 fallback, and TIOCGWINSZ, which computed its own answer live,
said 160x50.

That one disagreement produced all three things visible in the report: text
stopped two thirds of the way down the screen, `ls` laid out 160 columns into
an 80-column grid so words split across the wrap ("vers" / "ion"), and zsh's
cursor tracking was wrong on every line.

Fixed in two places, because either alone would leave the trap set:
gfx_attach_scanout() now calls vt_resize(), so the grids learn the real screen
the moment there is one; and TIOCGWINSZ reports v->cols/v->rows rather than
measuring again. One number, from the terminal being asked.

**Wrapping was eager.** A glyph printed in the last column moved the cursor to
the next line immediately. Real terminals set a pending-wrap flag and wrap when
the *next* glyph arrives -- which is why a line exactly as wide as the screen
takes one row and not two, and why a program can write the bottom-right cell
without scrolling.

zsh's partial-line marker depends on that rule directly: it writes exactly
COLUMNS-1 spaces and expects to still be on the line. With eager wrap it left a
reverse-video '#' above every prompt, which is the hashtag in the report. Both
are gone.

Verified by screendump: `ls /proc` now fits one line with "version" intact, no
markers, and output fills the screen to the last row. schfs-check passes.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01VQ7Qx8E1q1M1bbCq8QLHS2

kernel/dev/gfx.c

@@ -21,6 +21,7 @@
 #include "device.h"
 #include "display.h"
 #include "gfx.h"
+#include "vt.h"
 
 #define BACKSPACE 0x100
 #define CHAR_HEIGHT 16
@@ -47,6 +48,12 @@ gfx_attach_scanout(const struct fb_info *info)
 {
   scanout = *info;
   fb      = info->ptr;
+
+  // Tell the terminals how big the screen actually is. They were sized before
+  // this driver existed -- the PCI bus is walked long after the terminals are
+  // set up -- so until this call every grid is the 80x24 fallback. See
+  // vt_resize().
+  vt_resize();
 }
 
 const struct fb_info *