M1 Feat : Arrow-key decoding via ANSI

[im-nymii]

Teach the keyboard driver to emit standard CSI escape sequences :

\x1b[A ,\x1b[B ,\x1b[C ,\x1b[D

but you have to define them in src/include/ansi.h as :

#define ANSI_CSI "\x1b["

+ #define CURSOR_UP ANSI_CSI "A"
+ #define CURSOR_DOWN ANSI_CSI "B"
+ #define CURSOR_RIGHT ANSI_CSI "C"
+ #define CURSOR_LEFT ANSI_CSI "D"

for the arrow keys, and add a small parser in the shell to
interpret them. This mirrors how real terminals work and keeps input consistent
with our existing ANSI output emulator.