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-apply.md

@@ -0,0 +1,36 @@
+---
+id: fn-apply
+name: apply
+category: networking
+kind: builtin
+tokens: apply
+sig: apply(target, buf, len)
+tip: Fold received @Sync bytes back onto a model instance.
+order: 50
+---
+
+<code>apply</code> is the exact inverse of <code>serialize</code>: it reads <code>len</code> bytes from <code>buf</code> and copies each value back into the replicable-and-participating fields of the target model instance, in the same member-then-field order the serializer packed them. It is compiler-generated and dispatches on the instance's model, so it only touches synced fields — an unsynced field keeps whatever value it already held. Use it after <code>net_poll</code> to reconcile a client to the authority's state, or after a rollback to restore a snapshot you took with <code>serialize</code>. The buffer must have come from a serializer for a matching model, or the layout will not line up.
+
+Parameters:
+- `target` — the model instance (an `entity`) to write the fields onto
+- `buf` — the source buffer holding serialized bytes
+- `len` — the number of bytes in `buf` to read
+
+```ludic
+program ReconcilePlayer {
+  @Sync property Position { column: int = 0, row: int = 0 }
+  @Owned model Player { @Sync Position }
+
+  entry {
+    spawn Player { Position { column: 3, row: 4 } }
+    for (Position) in query [Position, {Player}] {
+      let player_id = self()
+      let snapshot_buffer = bytes(64)
+      let byte_count = serialize(player_id, snapshot_buffer)     # save authoritative state
+      Position.column = 999                                      # a mispredicted divergence
+      apply(player_id, snapshot_buffer, byte_count)             # reconcile back to the snapshot
+      print(Position.column)                                     # 3 — restored
+    }
+  }
+}
+```