forth: JIT cooperation hooks (vm-eligible flag + call-count + forth-hot-words)

lib/forth/runtime.sx

@@ -193,6 +193,12 @@
   forth-emit-str
   (fn (state s) (dict-set! state "output" (str (get state "output") s))))
 
+;; The body is always a plain SX lambda — primitives and colon-def
+;; bodies alike — which means the SX VM's JIT-on-first-call can lift
+;; the body directly into bytecode. We tag every word `:vm-eligible?
+;; true` so downstream JIT cooperation (a tracing layer, a hot-call
+;; counter) can pick out the JIT-friendly entries by metadata rather
+;; than by inspecting the body shape.
 (define
   forth-make-word
   (fn
@@ -202,6 +208,8 @@
       (dict-set! w "kind" kind)
       (dict-set! w "body" body)
       (dict-set! w "immediate?" immediate?)
+      (dict-set! w "vm-eligible?" true)
+      (dict-set! w "call-count" 0)
       w)))
 
 (define