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/events/kw-event.md

@@ -5,8 +5,29 @@ category: events
 kind: keyword
 tokens: event
 sig: event Name { field: T = default }
-tip: Declare a public event payload.
+tip: Declare a public event carrying a flat payload that listeners react to.
 order: 0
 ---
 
-Declare a public event payload.
+`event` declares a public event — a named signal carrying a flat payload of typed fields (each with a default; the payload may be empty). Where lifecycle hooks are the closed reactions the author compiles in, events are the <b>open runtime surface a game exposes to mods</b>: an in-language listener registers with `@On(Name)` and reads the payload fields by name, and `emit Name(field: value, …)` fires every listener in declaration order as a direct call. It all desugars to a generated function — there is no interpreter and no dispatch table — and a program that declares no `event` compiles byte-for-byte as before. Mark an event `cancellable` when a listener should be able to veto the action it announces.
+
+```ludic
+program EventExample {
+  event EnemyDefeated { points: int = 0 }
+
+  var score: int = 0
+
+  @On(EnemyDefeated) handler AddScore { score = score + points }
+  @On(EnemyDefeated) handler PlayChime { Screen.status("enemy down") }
+
+  handler ScoreOnKey phase Update {
+    if Input.key() == 'k' { emit EnemyDefeated(points: 10) }
+  }
+
+  handler DrawWorld phase Render {
+    Screen.clear(Color.MidnightBlue)
+    Screen.draw_number(x: 4, y: 4, value: score, color: Color.Gold, scale: 1)
+    Screen.show()
+  }
+}
+```