Complete mbedTLS cleanup - Removed all mbedTLS dependencies and updated documentation

- Moved mbedTLS directories to Trash/ (mbedtls/, mbedtls-install/, mbedtls-arm64-install/)
- Removed obsolete nostr_websocket_mbedtls.c implementation
- Updated nostr_websocket/Makefile to use OpenSSL instead of mbedTLS
- Updated nostr_websocket/README.md with OpenSSL migration notes
- Updated nostr_websocket/EXPORT_GUIDE.md with OpenSSL instructions
- All tests pass: crypto tests, static linking verification
- Build system fully functional with OpenSSL-only dependencies

nostr_websocket/EXPORT_GUIDE.md

@@ -8,11 +8,11 @@ The NOSTR WebSocket library consists of these key files for export:
 
 ### Core Files (Required)
 - `nostr_websocket_tls.h` - Header with all function declarations and constants
-- `nostr_websocket_mbedtls.c` - Main implementation using mbedTLS for SSL/TLS
+- `nostr_websocket_openssl.c` - Main implementation using OpenSSL for SSL/TLS
 - `../cjson/cJSON.h` and `../cjson/cJSON.c` - JSON parsing (lightweight)
 
 ### Dependencies
-- **mbedTLS** - For SSL/TLS support (wss:// connections)
+- **OpenSSL** - For SSL/TLS support (wss:// connections) - libssl, libcrypto
 - **Standard C libraries** - socket, networking, etc.
 
 ## Quick Integration
@@ -21,23 +21,29 @@ The NOSTR WebSocket library consists of these key files for export:
 ```bash
 # Copy the library files
 cp nostr_websocket_tls.h your_project/
-cp nostr_websocket_mbedtls.c your_project/
+cp nostr_websocket_openssl.c your_project/
 cp ../cjson/cJSON.h your_project/
 cp ../cjson/cJSON.c your_project/
 ```
 
-### 2. Install mbedTLS Dependency
+### 2. Install OpenSSL Dependency
 ```bash
 # Ubuntu/Debian
-sudo apt-get install libmbedtls-dev
+sudo apt-get install libssl-dev
 
-# Or build from source (see mbedTLS documentation)
+# CentOS/RHEL/Fedora
+sudo yum install openssl-devel
+# or
+sudo dnf install openssl-devel
+
+# macOS (via Homebrew)
+brew install openssl
 ```
 
 ### 3. Compile Your Project
 ```bash
-gcc -o my_nostr_app my_app.c nostr_websocket_mbedtls.c cJSON.c \
-    -lmbedtls -lmbedx509 -lmbedcrypto -lm
+gcc -o my_nostr_app my_app.c nostr_websocket_openssl.c cJSON.c \
+    -lssl -lcrypto -lm
 ```
 
 ## Basic Usage Example
@@ -131,16 +137,17 @@ The library supports both TCP (`ws://`) and TLS (`wss://`) automatically based o
 
 ### Linux/Unix
 - Works out of the box with standard development tools
-- Requires: gcc, mbedTLS development headers
+- Requires: gcc, OpenSSL development headers (libssl-dev)
 
-### Potential Windows Support
+### Windows Support
 - Would need Winsock2 adaptations in transport layer
-- mbedTLS is cross-platform compatible
+- OpenSSL is widely available on Windows
 
 ### Embedded Systems
 - Lightweight design suitable for embedded use
 - Memory usage: ~4KB per client + message buffers
 - No dynamic allocations in hot paths
+- OpenSSL provides optimized implementations for various architectures
 
 ## Library Design Benefits
 
@@ -178,7 +185,21 @@ The library handles all WebSocket protocol details, SSL/TLS, and NOSTR message f
 
 - Based on WebSocket RFC 6455
 - Implements NOSTR WebSocket conventions
-- SSL/TLS via proven mbedTLS library
+- SSL/TLS via industry-standard OpenSSL library
 - Tested with major NOSTR relays
 
+## Migration Notes
+
+If you were previously using the mbedTLS version of this library:
+
+### Code Changes Required
+- Update `#include` to reference `nostr_websocket_openssl.c` instead of `nostr_websocket_mbedtls.c`
+- Change linking flags from `-lmbedtls -lmbedx509 -lmbedcrypto` to `-lssl -lcrypto`
+- Install OpenSSL development headers instead of mbedTLS
+
+### API Compatibility
+- All function signatures remain identical
+- No changes to your application code required
+- Same performance characteristics and behavior
+
 This library provides a clean, efficient way to integrate NOSTR WebSocket functionality into any C project with minimal dependencies and maximum portability.