Initial schemas and validation with extension workplan

src/markitect_tool/schema/__init__.py

@@ -0,0 +1,31 @@
+"""Schema loading and validation for structured Markdown documents."""
+
+from markitect_tool.schema.loader import (
+    InvalidSchemaFormatError,
+    MarkdownSchema,
+    SchemaLoaderError,
+    SchemaNotFoundError,
+    load_schema_file,
+    load_schema_text,
+)
+from markitect_tool.schema.validator import (
+    SchemaValidationResult,
+    ValidationViolation,
+    validate_document,
+    validate_markdown_file,
+    validate_schema,
+)
+
+__all__ = [
+    "InvalidSchemaFormatError",
+    "MarkdownSchema",
+    "SchemaLoaderError",
+    "SchemaNotFoundError",
+    "SchemaValidationResult",
+    "ValidationViolation",
+    "load_schema_file",
+    "load_schema_text",
+    "validate_document",
+    "validate_markdown_file",
+    "validate_schema",
+]