Phase 6a: rename core vocabulary (game/main/component/archetype/system)

game/module -> program, main -> entry, component -> property,
archetype -> model, system -> handler. Done via a transitional self-hosting
bootstrap: parser accepts both -> reseed -> compiler source moved to new
keywords + parser tightened to new-only -> reseed (fixpoint holds). Old keywords
now rejected.

Token-safe corpus migration (tools/ludic-tools/rename_kw.c) leaves the LLVM
@main/entry: labels in emit strings untouched; goldens byte-identical. Editor
vocab (header/JetBrains/TextMate/emacs), check-docs wrapper, and doc fences
updated; error string 'unknown component' -> 'unknown property'. test.sh 14/14,
test-tools 28/0, check-vocabulary green. (Doc prose pass to follow.)

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

selfhost/tests/control.ludic

@@ -1,6 +1,6 @@
-game T {
+program T {
   fn fib(n: int) -> int { if n < 2 { return n };  return fib(n-1) + fib(n-2) }
-  main {
+  entry {
     print_int(fib(10))                 # 55
     let s = 0
     for i in 0 .. 10 { if i == 5 { break };  if i % 2 == 0 { continue };  s = s + i }

selfhost/tests/fixed.ludic

@@ -1,5 +1,5 @@
-game T {
-  main {
+program T {
+  entry {
     let half = 0.5
     let a = 1.5
     print_int(flr(a + half))          # flr(2.0) = 2

selfhost/tests/match_bits.ludic

@@ -1,9 +1,9 @@
-game T {
+program T {
   fn classify(c: int) -> int {
     match c { 65, 66 => { return 1 };  67 => { return 2 };  _ => { return 9 } }
     return 0
   }
-  main {
+  entry {
     print_int(classify(65))          # 1
     print_int(classify(67))          # 2
     print_int(classify(90))          # 9

selfhost/tests/slices.ludic

@@ -1,5 +1,5 @@
-game T {
-  main {
+program T {
+  entry {
     let xs = new []int
     print_int(len(xs))       # 0
     for i in 0 .. 20 { push(xs, i * i) }

selfhost/tests/structs.ludic

@@ -1,7 +1,7 @@
-game T {
+program T {
   struct P { x: int = 0, y: int = 7, next: P }
   fn bump(p: P) -> void { p.x = p.x + 100 }
-  main {
+  entry {
     let a = new P
     print_int(a.y)            # 7 default
     a.x = 5