chore(release): 1.26.0 [skip ci]

### What's New

- **Content extraction for RAG** — `doc.extract()` returns all document content in one call: blocks with full text and stable IDs, comments with anchored references, and tracked changes with excerpts. Every ID works directly with `scrollToElement()` for citation navigation.

### Improvements

- Standardized heading-level detection across extraction and API methods.
- Reused existing block-traversal logic to eliminate duplication and keep extraction consistent with the rest of the API.
- Added required-field validation to extract output schema.

Author: semantic-release-bot

packages/superdoc/package.json

@@ -1,7 +1,7 @@
 {
   "name": "superdoc",
   "type": "module",
-  "version": "1.25.0",
+  "version": "1.26.0",
   "license": "AGPL-3.0",
   "repository": {
     "type": "git",