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-port.md

@@ -0,0 +1,19 @@
+---
+id: kw-port
+name: port
+category: structure
+kind: keyword
+tokens: port
+sig: port Name { member: fn(T) -> R [= default], ... }
+tip: The questions a module asks the world, bound once by the program.
+order: 59
+---
+
+A <code>port</code> is what a module needs to ask the world, as named function members in primitive types. The program answers it once with <code>bind</code>; a member left unbound without a default is a compile error. Ports let a package ask a question without reaching into the module that knows the answer.
+
+```ludic
+# doc-check: skip — a module spans files
+export port ClockWorld {
+  rest_scale: fn() -> float
+}
+```