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/builtins/fn-push.md

@@ -5,8 +5,25 @@ category: builtins
 kind: builtin
 tokens: push
 sig: push(slice, x)
-tip: Append to a slice.
+tip: Append one element to the end of a growable slice.
 order: 6
 ---
 
-Append to a slice.
+Appends a value to the end of a slice, growing it by one element. Create the slice first with <code>new []T</code>, then <code>push</code> items onto it; afterward <code>len</code> reflects the new count and the element is reachable by index. Use it to build up lists at runtime — a queue of spawn requests, collected scores, parsed tokens — where you don't know the size in advance. The value's type must match the slice's element type.
+
+Parameters:
+- `slice` — the growable slice to append to
+- `x` — the element to append
+
+```ludic
+program BuildWaveList {
+  handler PlanWaves phase Start {
+    let wave_sizes = new []int
+    push(wave_sizes, 4)
+    push(wave_sizes, 6)
+    for index in 0 .. len(wave_sizes) {
+      print(wave_sizes[index])
+    }
+  }
+}
+```