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-serialize.md

@@ -1,12 +1,34 @@
 ---
 id: fn-serialize
-name: serialize / apply
+name: serialize
 category: networking
 kind: builtin
-tokens: serialize apply
-sig: serialize(e, buf) -> int   apply(e, buf, len)
-tip: Compiler-generated per-model replication of @Sync fields.
-order: 4
+tokens: serialize
+sig: serialize(target, buf) -> int
+tip: Pack a model instance's @Sync fields into a buffer; returns bytes written.
+order: 50
 ---
 
-Generated from the ECS schema per model: <code>serialize</code> writes an entity's <code>@Sync</code> fields into <code>buf</code> and returns the length; <code>apply</code> folds received bytes back onto an entity. Together they are the replication substrate the sugar builds on.
+<code>serialize</code> writes the replicated state of a model instance into <code>buf</code> and returns how many bytes it wrote. It is compiler-generated from the schema: it copies exactly the fields that are both <code>@Sync</code>-marked and participating in that instance's model, tightly packed in member-then-field order, and nothing else. This is the dispatcher over the per-model codecs, so it works for any spawned model whose fields sync. Use it to snapshot state before shipping it with <code>net_send</code> or before a rollback; the inverse is <code>apply</code>, which reads back the identical layout, and <code>sync_size</code> gives the byte count up front so you can size a buffer.
+
+Parameters:
+- `target` — the model instance (an `entity`) whose synced fields are read
+- `buf` — the destination buffer the packed bytes are written into
+
+```ludic
+program SnapshotPlayer {
+  @Sync property Position { column: int = 0, row: int = 0 }
+  property Health { @Sync current: int = 0, maximum: int = 0 }
+  @Owned model Player { @Sync Position, @Sync Health }
+
+  entry {
+    spawn Player { Position { column: 3, row: 4 }, Health { current: 50, maximum: 100 } }
+    for (Position, Health) in query [Position, Health, {Player}] {
+      let player_id = self()
+      let snapshot_buffer = bytes(64)
+      let byte_count = serialize(player_id, snapshot_buffer)     # pack column, row, current
+      print(byte_count)                                          # 12 = Position(8) + Health.current(4)
+    }
+  }
+}
+```