Increase node_log buffer to fix -Wformat-truncation warnings

The node_log macro used a 256-byte buffer for formatting log details,
but bucket names (64B) and keys (512B) can together require up to ~606
bytes, causing gcc to emit format-truncation warnings. Increase the
buffer to 1024 bytes to accommodate the worst case.

https://claude.ai/code/session_01HXKM6UjE3G4A29zTc7gFxo

src/server.c

@@ -64,7 +64,7 @@ static void node_log_impl(ServerState *state, const char *event, const char *det
 }
 
 #define node_log(state, event, fmt, ...) do {                    \
-    char _detail[256];                                           \
+    char _detail[1024];                                           \
     snprintf(_detail, sizeof(_detail), fmt, ##__VA_ARGS__);      \
     node_log_impl(state, event, _detail);                        \
 } while (0)