feat: Complete CouchDB migration and Docker configuration

- Add comprehensive CouchDB setup and configuration
- Update Docker files for CouchDB compatibility
- Create Kubernetes manifests for CouchDB deployment
- Add migration scripts and documentation
- Update seeding scripts to support both CouchDB and MongoDB
- Add docker-compose for local development
- Create comprehensive setup and deployment guides

🤖 Generated with [AI Assistant]

Co-Authored-By: AI Assistant <noreply@ai-assistant.com>

node_modules/mongoose/lib/schema/union.js

@@ -0,0 +1,105 @@
+'use strict';
+
+/*!
+ * ignore
+ */
+
+const SchemaUnionOptions = require('../options/schemaUnionOptions');
+const SchemaType = require('../schemaType');
+
+const firstValueSymbol = Symbol('firstValue');
+
+/*!
+ * ignore
+ */
+
+class Union extends SchemaType {
+  constructor(key, options, schemaOptions = {}) {
+    super(key, options, 'Union');
+    if (!options || !Array.isArray(options.of) || options.of.length === 0) {
+      throw new Error('Union schema type requires an array of types');
+    }
+    this.schemaTypes = options.of.map(obj => options.parentSchema.interpretAsType(key, obj, schemaOptions));
+  }
+
+  cast(val, doc, init, prev, options) {
+    let firstValue = firstValueSymbol;
+    let lastError;
+    // Loop through each schema type in the union. If one of the schematypes returns a value that is `=== val`, then
+    // use `val`. Otherwise, if one of the schematypes casted successfully, use the first successfully casted value.
+    // Finally, if none of the schematypes casted successfully, throw the error from the last schema type in the union.
+    // The `=== val` check is a workaround to ensure that the original value is returned if it matches one of the schema types,
+    // avoiding cases like where numbers are casted to strings or dates even if the schema type is a number.
+    for (let i = 0; i < this.schemaTypes.length; ++i) {
+      try {
+        const casted = this.schemaTypes[i].cast(val, doc, init, prev, options);
+        if (casted === val) {
+          return casted;
+        }
+        if (firstValue === firstValueSymbol) {
+          firstValue = casted;
+        }
+      } catch (error) {
+        lastError = error;
+      }
+    }
+    if (firstValue !== firstValueSymbol) {
+      return firstValue;
+    }
+    throw lastError;
+  }
+
+  // Setters also need to be aware of casting - we need to apply the setters of the entry in the union we choose.
+  applySetters(val, doc, init, prev, options) {
+    let firstValue = firstValueSymbol;
+    let lastError;
+    // Loop through each schema type in the union. If one of the schematypes returns a value that is `=== val`, then
+    // use `val`. Otherwise, if one of the schematypes casted successfully, use the first successfully casted value.
+    // Finally, if none of the schematypes casted successfully, throw the error from the last schema type in the union.
+    // The `=== val` check is a workaround to ensure that the original value is returned if it matches one of the schema types,
+    // avoiding cases like where numbers are casted to strings or dates even if the schema type is a number.
+    for (let i = 0; i < this.schemaTypes.length; ++i) {
+      try {
+        let castedVal = this.schemaTypes[i]._applySetters(val, doc, init, prev, options);
+        if (castedVal == null) {
+          castedVal = this.schemaTypes[i]._castNullish(castedVal);
+        } else {
+          castedVal = this.schemaTypes[i].cast(castedVal, doc, init, prev, options);
+        }
+        if (castedVal === val) {
+          return castedVal;
+        }
+        if (firstValue === firstValueSymbol) {
+          firstValue = castedVal;
+        }
+      } catch (error) {
+        lastError = error;
+      }
+    }
+    if (firstValue !== firstValueSymbol) {
+      return firstValue;
+    }
+    throw lastError;
+  }
+
+  clone() {
+    const schematype = super.clone();
+
+    schematype.schemaTypes = this.schemaTypes.map(schemaType => schemaType.clone());
+    return schematype;
+  }
+}
+
+/**
+ * This schema type's name, to defend against minifiers that mangle
+ * function names.
+ *
+ * @api public
+ */
+Union.schemaName = 'Union';
+
+Union.defaultOptions = {};
+
+Union.prototype.OptionsConstructor = SchemaUnionOptions;
+
+module.exports = Union;