Sidenote + Page als kindelemente von letterText

CLAUDE.md

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+# CLAUDE.md
+
+This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
+
+## Project Overview
+
+This is a digital humanities project for editing J.M.R. Lenz's letters. The project maintains XML files containing historical letter texts, metadata, and annotations, following the "lenz-archiv.de" XML schema.
+
+## Repository Structure
+
+- `data/xml/` - Core XML files containing letter data:
+  - `briefe.xml` - Letter texts with rich markup for formatting and cross-references
+  - `meta.xml` - Letter metadata (dates, senders, receivers, locations)
+  - `references.xml` - Person, location, and apparatus definitions
+  - `traditions.xml` - Text provenance and editorial apparatus
+- `data/xsd/` - XML Schema Definition files that validate the XML structure
+- `scripts/` - Python utilities for data processing and validation
+
+## Commands
+
+### Validation and Linting
+```bash
+# Validate XML cross-references (main quality check)
+python scripts/lint_verweise.py
+
+# Install Python dependencies for scripts
+pip install lxml
+```
+
+### Data Transformation
+```bash
+# Transform meta.xml date structures
+python scripts/transform-meta-sort.py INPUT.xml OUTPUT.xml
+```
+
+## XML Schema Architecture
+
+The project uses a custom XML namespace `https://lenz-archiv.de` with modular XSD files:
+- `lenz.xsd` - Main schema file
+- `textelements.xsd` - Text formatting and semantic markup elements
+- `common.xsd`, `briefe.xsd`, `meta.xsd`, `references.xsd` - Component schemas
+
+Key XML elements follow a hierarchical structure under `<opus>` root elements, with specialized namespaced elements for cross-references between files.
+
+## Validation Workflow
+
+The `lint_verweise.py` script performs cross-file reference validation:
+- Verifies `letterText/@letter` references exist in `meta.xml`
+- Validates person references (`@ref` attributes) against `references.xml`
+- Checks location and apparatus definition references
+- Reports errors with file paths and line numbers for GitHub Actions integration
+
+GitHub Actions automatically runs validation on XML file changes via `.github/workflows/verweise.yml`.