feat(wasm): add typed container trees with fixed JS construction

[zxch3n]

This adds a typed, independent representation of visible document values that preserves real container identities without a path table or ambiguity with ordinary objects.

const roots = doc.toContainerTree();
const selected = doc.toContainerTree({ roots: ["settings", "profile"] });
const subtree = map.toContainerTree({ text: "delta" });
const window = list.toContainerTreeSlice(20, 40);
// window: { cid, start, totalLength, items }

Documents and all six attached container kinds expose toContainerTree(). Containers are { type, cid, value }; ordinary values are opaque Value nodes. The text option applies recursively, including Tree metadata. TypeScript infers the receiver kind and text format. Detached containers throw because they have no attached identity.

Root selection happens before value traversal; unknown/hidden roots are omitted without creating them. List/MovableList slices are separate from complete container nodes and include clamped coordinates and total length, read under one state lock. Bounds are nonnegative u32 integers, end-exclusive; obtaining the parent shallow list remains O(N).

The implementation traverses ephemeral shallow values and constructs JS objects with fixed helpers. Keys/peer strings are reused per read; binary buffers are owned. No public transport protocol, callback decoder, path table, or lifetime cache. Reads do not commit. The unpublished readState API is replaced; existing released getDeepValueWithID remains unchanged.

Validation: final release packaging for all targets; 372 Vitest tests passed (2 skipped, 2 todo), TypeScript, 4 Deno and 4 Bun tests passed. Coverage includes opaque data, recursive deltas, Tree metadata, IDs, ownership, special properties, root filtering without traversal of excluded deep subtrees, detached containers, slice bounds and inferred types. Mirror integration against the built package passes 453 core tests. Related Mirror integration: loro-dev/loro-mirror#98.

Performance experiments retain fixed construction: bounded UTF-8/UTF-16 string batching did not provide consistent end-to-end gains across Node and Chromium. Those prototypes are not included in this PR.

[github-actions]

WASM Size Report

• Original size: 3145.28 KB
• Gzipped size: 1041.30 KB
• Brotli size: 730.39 KB