Again, I’m not a lawyer. What follows is my own personal interpretation.
There is a major distinction between OrthancToolsJS and the question of the original poster: In your case, you don’t provide Orthanc on an AWS server to customers, you use unmodified versions of Orthanc, and you publicly provide your source code, so the AGPL is not triggered for those three reasons.
Regarding the question about a proprietary software interacting with an AGPL-licensed software through network communications, check out the FAQ from the Free Software Foundation:
"In AGPLv3, what counts as “interacting with [the software (Orthanc)] remotely through a computer network?
If the program is expressly designed to accept user requests and send responses over a network, then it meets these criteria. Common examples of programs that would fall into this category include web and mail servers, interactive web-based applications, and servers for games that are played online. [This is the case of Orthanc]
If a program is not expressly designed to interact with a user through a network, but is being run in an environment where it happens to do so, then it does not fall into this category. For example, an application is not required to provide source merely because the user is running it over SSH, or a remote X session. [This is not the case of Orthanc]"
I also remember the goal of the AGPL license:
“The GNU Affero General Public License is a modified version of the ordinary GNU GPL version 3. It has one added requirement: if you run a modified program on a server and let other users communicate with it there, your server must also allow them to download the source code corresponding to the modified version running there.”
My understanding is the following: The AGPL is about the server-side code, not about the client-side code. If some client software (such as OrthancToolsJS) contacts some Orthanc server that is running somewhere on a cloud server, the source code of this client software is allowed to be kept proprietary. However, if the cloud server runs a modified version of Orthanc (i.e. if some custom C/C++ plugin, Lua script, Python script is installed, or if there were modifications applied to the source code), with at least one AGPL-licensed plugin (PostgreSQL, MySQL, S3, Orthanc/Osimis/Stone Web viewers…), and if this Orthanc server can be accessed by some external client, then all the source code that leads to this modified version of Orthanc must be published under the GPL or AGPL license.