Keyboard lights, TLB shootdowns, battery in sysfs, /proc/pid/maps

Caps, Num and Scroll Lock now light their LEDs on PS/2 and USB keyboards,
share one state between keyboards, and stop toggling on key repeat. X sets
them through evdev writes while it holds the keyboard.

Unmapping memory in a process with threads on other CPUs now flushes their
TLBs with an IPI. Without it a freed page stayed reachable through stale
translations, which corrupted Epiphany's heap on SMP.

ACPI batteries and AC adapters appear under /sys/class/power_supply.
/proc/<pid>/maps lists file mappings, and a process killed by a fault
names the file and offset it died in. r8169 gets a 256-entry RX ring.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01S1giNvrHTrPMPw7V6x1kQ4

kernel/core/main.c

@@ -266,6 +266,7 @@ kmain(uint64 fb_addr)
   ioapicinit();
   if (boot_verbose) cprintf("verbose boot: ioapicinit done\n");
   irq_init();       // must precede any driver init that registers a handler
+  tlb_init();       // the shootdown vector, before any second CPU runs threads
   if (boot_verbose) cprintf("verbose boot: irq_init done\n");
   // Before the keyboard and mouse, which start producing events the moment
   // their handlers are registered.