新增3.4版本支持

lib/3.4/README.md

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+# Spine 3.4 runtime
+
+Bundled from the official `3.4.02` tag, commit `ef5013143178918ddfc7cabfbddeae7aec7cf84e`, `spine-ts/build/spine-canvas.js`.
+
+Local correction: `SkeletonJson` path-length loop writes `lengths[i]`, not `lengths[i++]`. The original increments twice and reads beyond the source array, producing missing/NaN lengths.
+
+The plugin provides binary decoding and the `AtlasAttachmentLoader` name alias in `js/spine-legacy-binary.js`. Rendering uses the 3.4 attachment vertex API in `js/spine-canvas-clipping.js`. 3.4 has no clipping attachments; no newer attachment types are synthesized.
+
+License: `LICENSES/Spine-3.4-License.txt`.