Add benchmark tests and optimize encryption performance

- Introduced comprehensive benchmark tests for NIP-44 and NIP-4 encryption/decryption, including various message sizes and round-trip operations.
- Implemented optimizations to reduce memory allocations and CPU processing time in encryption functions, focusing on pre-allocating buffers and minimizing reallocations.
- Enhanced error handling in encryption and decryption processes to ensure robustness.
- Documented performance improvements in the new PERFORMANCE_REPORT.md file, highlighting significant reductions in execution time and memory usage.

pkg/encoders/text/escape.go

@@ -26,6 +26,16 @@ package text
 // JSON parsing errors when events with binary data in content are sent to relays.
 func NostrEscape(dst, src []byte) []byte {
 	l := len(src)
+	// Pre-allocate buffer if nil to reduce reallocations
+	// Estimate: worst case is all control chars which expand to 6 bytes each (\u00XX)
+	// but most strings have few escapes, so estimate len(src) * 1.5 as a safe middle ground
+	if dst == nil && l > 0 {
+		estimatedSize := l * 3 / 2
+		if estimatedSize < l {
+			estimatedSize = l
+		}
+		dst = make([]byte, 0, estimatedSize)
+	}
 	for i := 0; i < l; i++ {
 		c := src[i]
 		if c == '"' {