Baseline: Ludic compiler + toolchain, Phase 1 syntax fixes complete

Self-hosted compiler (selfhost/*.ludic), runtime, examples, editor tooling,
and docs. Phase 1 of the syntax-redesign cohesion pass has landed:
edge-system fix, signature-query, when-alias, and the documentation truth-pass.
Suite green (14/14), C-free bootstrap fixpoint holds.

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

selfhost/tests/structs.ludic

@@ -0,0 +1,20 @@
+game T {
+  struct P { x: int = 0, y: int = 7, next: P }
+  fn bump(p: P) -> void { p.x = p.x + 100 }
+  main {
+    let a = new P
+    print_int(a.y)            # 7 default
+    a.x = 5
+    let b = a
+    b.x = 9
+    print_int(a.x)            # 9 (reference)
+    bump(a)
+    print_int(a.x)            # 109
+    let c = new P
+    c.x = 2
+    a.next = c
+    print_int(a.next.x)      # 2 chained
+    a.next.x = 42
+    print_int(c.x)           # 42
+  }
+}