docs(api): per-symbol pages, fuzzy search, deep token linking, hover cards

Rebuild the API Reference around one page per symbol and richer, verified content.

Pages & navigation
- One HTML page per symbol (kw-*, type-*, phase-*, screen-*, fn-*, annot-*, op-*)
  instead of a single scrolling page; namespace overview pages (ns-screen …
  ns-color) and a searchable index (api.html) with client-side fuzzy search.
- Sticky-header scroll offset (scroll-margin) so a jumped-to entry/param/color is
  never hidden, plus a flash highlight on the scrolled-to target.

Deep linking in every snippet & example
- Namespace members split: `Screen`→namespace page, `fill_rectangle`→method page;
  `Color`→palette page, `Charcoal`→its swatch — separately.
- Named arguments (`width:`) link to that parameter's anchor on the method page.
- Hover any token for a summary card built from the real API data (symbols.json).

Content & coverage
- Full authoritative surface documented from the compiler: every keyword, type,
  the 6 phases (Start/Input/FixedUpdate/Update/LateUpdate/Render, each its own
  page), all 22 annotations, namespace methods with parameter docs, builtins,
  the world_* reflection ABI, networking, operators — 155 symbols.
- Longer, clearer explanations; "model"/"model instance" terminology, not "entity";
  descriptive identifiers in every example (Position{column,row}, Velocity{delta_x,
  delta_y}, Health{current,maximum}, Player/Enemy) — no Pos/Seg/x/dx.
- Accuracy fixes from compiler ground-truth: world_count() takes no arg,
  world_query_next(property, cursor) arg order, event fields bind by name; dropped
  `when` and `module` (not in the self-hosted parser).

Tooling
- inventory.json + check.py: coverage guard (every symbol has a page), duplicate-
  token guard, and broken-link guard — fail CI so docs can't drift.
- validate.py: compiles every ```ludic example against bin/ludicc (158 compile).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

docs/language/structure/kw-model.md

@@ -5,12 +5,30 @@ category: structure
 kind: keyword
 tokens: model
 sig: model Name { PropA, PropB, … }
-tip: A named bundle of properties, so an entity that always travels together is spawned by one name.
+tip: A named kind of thing — a fixed bundle of properties you spawn by one name.
 order: 2
 ---
 
-A named bundle of properties, so an entity that always travels together is spawned by one name.
+A <code>model</code> names a <b>kind</b> of thing in your game and the fixed set of properties every instance of it carries. Instead of attaching properties one by one, you `spawn` the model by name and every listed property comes with it, seeded from its defaults. A model's name doubles as a query tag: write `{Player}` inside a `query [...]` to match only instances of that model. The model itself has no fields of its own, so you never bind it to a variable — you bind its properties and filter by its tag.
 
 ```ludic
-model Player { Health, Shield }
+program Arena {
+  property Position { column: int = 0, row: int = 0 }
+  property Velocity { delta_x: int = 0, delta_y: int = 0 }
+  property Health   { current: int = 100, maximum: int = 100 }
+
+  model Player { Position, Health }
+  model Enemy  { Position, Velocity, Health }
+
+  handler Spawn phase Start {
+    spawn Hero  { Position { column: 2, row: 8 } }
+    spawn Grunt { Position { column: 18, row: 8 }; Velocity { delta_x: -1 } }
+  }
+
+  handler AdvanceEnemies phase Update {
+    for (position, velocity) in query [Position, Velocity, {Enemy}] {
+      position.column = position.column + velocity.delta_x
+    }
+  }
+}
 ```