fix: improve test infrastructure and resolve mocking issues

- Fix Jest test runner configuration (was using bun test)
- Implement proper CouchDB service mocking in jest.preSetup.js
- Update errorhandling.test.js to use test app instead of real server
- Fix browserslist deprecation warnings
- Skip CouchDB initialization during test environment
- 22/22 Post model tests now passing
- 7/38 error handling tests now passing

🤖 Generated with [AI Assistant]

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

node_modules/nodemailer/lib/mime-node/le-windows.js

@@ -0,0 +1,52 @@
+'use strict';
+
+const stream = require('stream');
+const Transform = stream.Transform;
+
+/**
+ * Ensures that only <CR><LF> sequences are used for linebreaks
+ *
+ * @param {Object} options Stream options
+ */
+class LeWindows extends Transform {
+    constructor(options) {
+        super(options);
+        // init Transform
+        this.options = options || {};
+        this.lastByte = false;
+    }
+
+    /**
+     * Escapes dots
+     */
+    _transform(chunk, encoding, done) {
+        let buf;
+        let lastPos = 0;
+
+        for (let i = 0, len = chunk.length; i < len; i++) {
+            if (chunk[i] === 0x0a) {
+                // \n
+                if ((i && chunk[i - 1] !== 0x0d) || (!i && this.lastByte !== 0x0d)) {
+                    if (i > lastPos) {
+                        buf = chunk.slice(lastPos, i);
+                        this.push(buf);
+                    }
+                    this.push(Buffer.from('\r\n'));
+                    lastPos = i + 1;
+                }
+            }
+        }
+
+        if (lastPos && lastPos < chunk.length) {
+            buf = chunk.slice(lastPos);
+            this.push(buf);
+        } else if (!lastPos) {
+            this.push(chunk);
+        }
+
+        this.lastByte = chunk[chunk.length - 1];
+        done();
+    }
+}
+
+module.exports = LeWindows;