kill + ps: implement SYS_KILL (pid 1 immortal) and a ps tool

- PCB gains PROC_PROG (running program id), set by exec, inherited on fork.
- sys_kill(pid): reject pid 1 (immortal) and unknown/dead pids; mark the target
  zombie, reparent its children to init, wake its parent if blocked in wait;
  schedule away if a process kills itself. Reuses FindPcbByPid/ReparentToInit.
- sys_ps(slot,buf)->{pid,state,prog}; sys_progname(id) via NameTable reverse
  lookup. NameTable gains sh/ps/kill.
- libc: kill/psget/progname; tools ps (pid state cmd) and kill <pid>.
- verified: ps lists sh(B)+ps(R); kill 1 refused; kill 42 fails.

1 files changed, 16 insertions, 0 deletions

diff --git a/src/programs.asm b/src/programs.asm
index 1a7092e..f21d40b 100644
--- a/src/programs.asm
+++ b/src/programs.asm
@@ -88,6 +88,12 @@ ProgSave:
 SECTION "prog_rm",     ROMX[$4000], BANK[17]
 ProgRm:
     INCBIN "c/rm.bin"
+SECTION "prog_ps",     ROMX[$4000], BANK[18]
+ProgPs:
+    INCBIN "c/ps.bin"
+SECTION "prog_kill",   ROMX[$4000], BANK[19]
+ProgKill:
+    INCBIN "c/kill.bin"
 
 ; -----------------------------------------------------------------------------
 ; PROG_SH (bank 3) - the shell, now written in C (c/sh.c): parses >/</| and
@@ -162,6 +168,10 @@ ProgramTable::
     dw ProgSave
     db LOW(BANK(ProgRm)), HIGH(BANK(ProgRm))
     dw ProgRm
+    db LOW(BANK(ProgPs)), HIGH(BANK(ProgPs))
+    dw ProgPs
+    db LOW(BANK(ProgKill)), HIGH(BANK(ProgKill))
+    dw ProgKill
 
 ; -----------------------------------------------------------------------------
 ; NameTable (ROM0) - command name -> program id, searched by sys_lookup.
@@ -198,4 +208,10 @@ NameTable::
     db PROG_SAVE
     db "rm", 0
     db PROG_RM
+    db "sh", 0
+    db PROG_SH
+    db "ps", 0
+    db PROG_PS
+    db "kill", 0
+    db PROG_KILL
     db 0