editor_words.c: zero tractable words (first such file in this sweep) --
every word routes through the same deferred block-window cache as
block_words.c, and EDIT is an interactive stdin/stdout REPL loop, not a
single-step transition.
format_words.c: 17 of 19 registered words modeled (# and #S deferred,
multi-precision division out of scope). Two genuine C findings recorded:
(1) DECIMAL/HEX/OCTAL write only the FORTH-visible memory cell at
base_addr, never the separate vm->base host-mirror field that number
OUTPUT words actually read -- proved formally
(decimal_does_not_change_vm_base et al.), so HEX/OCTAL/DECIMAL silently
never affect printed output, only parsed input. (2) ? and DUMP cast the
popped cell directly to a host pointer and dereference it, bypassing
vm_addr_ok entirely -- an out-of-VM-bounds read, not modeled since it
isn't a vm->memory access at all.
Adds base_addr/hold_addr/hold_pos to vm_state (StarForth_Base.thy),
matching the scr_addr/here pattern from earlier files.
