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/ecs/fn-world_get.md

@@ -1,12 +1,37 @@
 ---
 id: fn-world_get
-name: world_get / world_set / world_has …
+name: world_get
 category: ecs
 kind: builtin
-tokens: world_get world_set world_has world_count world_spawn
-sig: world_get(entity, prop, field) -> int
-tip: The reflection ABI: read and write the world by numeric id, for tools and mods.
-order: 8
+tokens: world_get
+sig: world_get(target, property, field) -> int
+tip: Read one field of a model instance by numeric id (reflection ABI).
+order: 50
 ---
 
-The reflection ABI: read and write the world by numeric id, for tools and mods. See also world_count, world_spawn.
+<code>world_get</code> reads a single field of a model instance entirely by numeric id, returning its value as an `int`. It is the id-based counterpart to the ordinary `position.column` field access that queries give you — used when the property is not known at compile time, as in a mod or a generic tool. You supply the target instance (an `entity`), the property id (from `world_prop_id`), and the field id (from `world_field_id`); the result is the stored value. Pair it with `world_set` to write. Reading a field of an instance that lacks the property is not meaningful, so guard with `world_has` first if unsure.
+
+Parameters:
+- `target` — the model instance to read from, an `entity` handle
+- `property` — the property id, from `world_prop_id`
+- `field` — the field id within that property, from `world_field_id`
+
+```ludic
+program ReadField {
+  property Position { column: int = 0, row: int = 0 }
+  model Player { Position }
+
+  handler Boot phase Start {
+    spawn Hero { Position { column: 7, row: 2 } }
+  }
+
+  handler Inspect phase Update {
+    let position_property = world_prop_id("Position")
+    let column_field = world_field_id(position_property, "column")
+    for (position) in query [Position, {Player}] {
+      let value = world_get(self(), position_property, column_field)
+      Screen.status(str(value))
+    }
+  }
+}
+```