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/slices.ludic

@@ -0,0 +1,11 @@
+game T {
+  main {
+    let xs = new []int
+    print_int(len(xs))       # 0
+    for i in 0 .. 20 { push(xs, i * i) }
+    print_int(len(xs))       # 20
+    print_int(xs[19])        # 361
+    xs[3] = 777
+    print_int(xs[3])         # 777
+  }
+}