Refactor and consolidate test suite

- Moved old tests from tests/old/ to main tests/ directory
- Renamed nostr_test_bip32.c to bip32_test.c for consistency
- Renamed nostr_crypto_test.c to crypto_test.c for consistency
- Renamed wss_test.c and moved from old directory
- Fixed unused variable warning in bip32_test.c
- Updated build system and workspace rules
- Cleaned up old compiled test executables
- Updated nostr_common.h and core_relays.c
- Removed obsolete nostr_core.h.old backup file

This consolidates all active tests into the main directory and removes
outdated test files while maintaining a clean, organized structure.

build.sh

@@ -272,6 +272,8 @@ SOURCES="$SOURCES nostr_core/crypto/nostr_chacha20.c"
 SOURCES="$SOURCES cjson/cJSON.c"
 SOURCES="$SOURCES nostr_core/utils.c"
 SOURCES="$SOURCES nostr_core/nostr_common.c"
+SOURCES="$SOURCES nostr_core/core_relays.c"
+SOURCES="$SOURCES nostr_websocket/nostr_websocket_openssl.c"
 
 # Add secp256k1 library path based on architecture
 case $ARCHITECTURE in