feat(lang): 0.R1 - actions and reducers

action Name { fields } is a typed record; reducer State on Action(s: mut State, a: Action) { ... }
in the module that owns the state takes exactly that state and the action (a second state is
refused); dispatch Action { fields } queues one from anywhere, the queue supplied by the runtime.
The queue is drained at the end of every phase of the frame loop, after every phase of ludic.base's
core_tick_all, and by drain_actions(): in dispatch order, each action's reducers in the order of
their states' names, an action a reducer dispatches queued behind, a queue still growing after 64
rounds stopped with the action named. Examples actions/pack, phases, runaway; rejects for a second
state, a reducer on a non-action and an unknown dispatch; ludic.base's actions_test; LANGUAGE.md.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

examples/actions/runaway.ludic

@@ -0,0 +1,15 @@
+# runaway.ludic - 0.R: a reducer that dispatches what dispatches it is stopped, by name, after
+# 64 rounds, rather than spinning
+program Runaway {
+  state Echo { n: int = 0 }
+  action Ping {}
+  reducer Echo on Ping(e: mut Echo, a: Ping) {
+    e.n += 1
+    dispatch Ping {}
+  }
+  entry {
+    dispatch Ping {}
+    drain_actions()
+    print("not reached")
+  }
+}