docs/language: a page for every keyword and attribute the vocabulary has

Keywords: module uses friend export internal numbers unsafe mut port bind action
reducer registry of as from def open alias component prop view (structure),
shows lasts then loads (scenes), system (ecs), dispatch (control), true false
null (operators). Attributes: @Ref @OneOf @Range @Unit @Asset @Color, @Node /
@Clip / @Material, @Tint @Derived, @Text / @Multiline, @Key, @AppendOnly /
@ByKey, @PerMap / @Chunked, @frame @max, @owns / @creates / @releases,
@deterministic @alloc_ok. Each is in tools/docgen/inventory.json; every fence
that is not marked skip parses (ludicc --fmt). annot-clearcolor's token loses its
quotes, which no reader strips.

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

docs/language/structure/kw-action.md

@@ -0,0 +1,16 @@
+---
+id: kw-action
+name: action
+category: structure
+kind: keyword
+tokens: action
+sig: action Name { field: Type, ... }
+tip: What the player asked for, dispatched and applied by each state's reducer.
+order: 61
+---
+
+An <code>action</code> is a record that says what was asked for in the game's words (<code>Move</code>, <code>OpenPack</code>). Input code <code>dispatch</code>es it, and every <code>reducer</code> declared on it changes its own state. The queue drains at the end of every frame phase, each action's reducers in the order of their states' names.
+
+```ludic
+action Move { dx: int = 0, dy: int = 0 }
+```