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>

examples/lib/arena.ludic

@@ -0,0 +1,34 @@
+# ============================================================================
+# arena.ludic — a game that links the Ludic shared library next to it.
+#
+#   ludicc examples/lib/combat.ludic --shared -o build/libcombat.dylib
+#   ludicc examples/lib/arena.ludic  -o build/arena -Lbuild -lcombat
+#
+# `extern fn` binds a name to a symbol resolved at link time. The library the
+# symbols come from happens to be written in Ludic, but nothing here depends on
+# that: the same declaration binds a C, Rust or Zig library just as well. This
+# is how Ludic reaches the outside world without a C shim.
+# ============================================================================
+game Arena {
+
+  extern fn damage(attack: int, armour: int, roll: int) -> int = "damage"
+  extern fn hits_to_kill(hp: int, attack: int, armour: int) -> int = "hits_to_kill"
+  extern fn xp_for(level: int, kills: int) -> int = "xp_for"
+
+  component Fighter { hp: int = 30, attack: int = 9, armour: int = 2 }
+
+  system Boot phase Start {
+    spawn Hero { Fighter = { hp = 40, attack = 12, armour = 3 } }
+    spawn Orc  { Fighter = { hp = 24, attack = 7,  armour = 1 } }
+  }
+
+  system Fight phase Update {
+    for (f) in query [Fighter] {
+      print_int(damage(f.attack, f.armour, 0))
+      print_int(damage(f.attack, f.armour, 20))
+      print_int(hits_to_kill(f.hp, f.attack, f.armour))
+    }
+    print_int(xp_for(3, 4))
+    quit()
+  }
+}