fix: Windows spawn, prefab path, preview API, asset deps, error messages; add execute-context resource, tool descriptions, scene/script/asset tools

Bug fixes (verified against Cocos Creator 3.8.8):
- diagnostics: shell:true for .cmd/.bat on Windows (T125/T126)
- prefabs: duplicatePrefab target resolves under assets/ (T420)
- cocos-project: add preview.open candidate for 3.8.8 (T444)
- assets-advanced: detect directory assets in inspectAssetDependencies (T110)
- scene: improve component-not-found errors with compilation hint (T429)

Documentation improvements:
- tool-registry: add enum and injected vars to execute_javascript, path format examples, asset ref limitation note
- resources: add cocos://mcp/execute-context resource with variables, patterns, pitfalls

New tools (core 37->38, full 101->110):
- scene-management: create_scene, query_scene_state (core), copy_paste_node, rename_node, reparent_node
- scripts: create_script with component/plain templates
- prefabs: create_prefab
- assets-advanced: batch_asset_ops, find_unused_assets

CONTRIBUTING.md

@@ -88,6 +88,35 @@ When adding a new tool:
 6. Add clear input schema descriptions so AI clients can choose the tool correctly.
 7. Test the tool with `tools/list` and `tools/call`.
 
+### Asset Creation via Template Files
+
+When a tool creates a new Cocos asset with a complex serialized format
+(scene, prefab, animation clip, material, etc.), **store a template file in
+`resources/` and pass its content to `asset-db: create-asset`** rather than
+hard-coding JSON strings in source.
+
+Why:
+
+- Cocos serialized formats are version-specific and contain many required
+  sub-objects (e.g. a scene needs `cc.SceneGlobals` → `cc.AmbientInfo`,
+  `cc.ShadowsInfo`, `cc.SkyboxInfo`, `cc.FogInfo`, `cc.OctreeInfo`,
+  `cc.SkinInfo`, `cc.LightProbeInfo`, `cc.PostSettingsInfo`).  Missing or
+  misnamed classes cause silent import failures or runtime errors.
+- A real template file can be created/verified in the Cocos editor and
+  updated by simply replacing the file.
+- `asset-db: create-asset(url, content)` handles `.meta` generation and
+  import in one step — no need for `fs.writeFileSync` + `refreshAssets`.
+
+Pattern:
+
+1. Create the template file at `resources/template.<ext>` (e.g.
+   `resources/template.scene`).
+2. Add `"resources/"` to the `files` array in `package.json` so it ships
+   in the npm package.
+3. In the tool handler, read the template with `fs.readFileSync`, optionally
+   replace `_name` fields, then call `create-asset` with the content string.
+4. Export a pure helper (e.g. `buildSceneContent`) for unit testing.
+
 ## Documentation
 
 The documentation is bilingual: