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/networking/fn-is_owner.md

@@ -0,0 +1,33 @@
+---
+id: fn-is_owner
+name: is_owner
+category: networking
+kind: builtin
+tokens: is_owner
+sig: is_owner(target) -> bool
+tip: Whether the local peer owns a model instance.
+order: 50
+---
+
+<code>is_owner</code> reports whether the local peer owns a given model instance — it compares the instance's stored owner (see <code>owner</code>) against <code>local_id</code> and returns the result. It only makes sense for instances of an <code>@Owned</code> model, and it is what <code>@Predicted</code> handler dispatch consults to decide whether the owning client should run a control handler speculatively. Prefer this over reading <code>owner</code> and comparing ids yourself. A freshly spawned, unowned instance returns false everywhere until the authority assigns it with <code>set_owner</code>.
+
+Parameters:
+- `target` — the model instance (an `entity`) to test
+
+```ludic
+program CheckOwnership {
+  @Sync property Position { column: int = 0, row: int = 0 }
+  @Owned model Player { @Sync Position }
+
+  entry {
+    spawn Player { Position { column: 5, row: 6 } }
+    for (Position) in query [Position, {Player}] {
+      let player_id = self()
+      set_owner(player_id, 7)
+      print(is_owner(player_id))       # 0 — local id 0 does not own peer 7's instance
+      set_owner(player_id, 0)
+      print(is_owner(player_id))       # 1 — now the local peer owns it
+    }
+  }
+}
+```