A few questions I have for this:
First, how to I integrate the clock with the Map/Terrain/Pathfinding subsystem? I don't just want to start passing the clock through everything, but it seems like, with this task, as well as the Cost Stamp and Record History issues, time will be needed in the pathfinding system. How will this be integrated?

Also, would it be good practice to include non-time based overrides for CostField set_cost which simply set the time to TIME_ZERO for initialization? I have done this for the CostField function that is used by the Map class, but only to avoid needing to pass in a time_t from the map.

Lastly, how do I run with debugging using Visual Studio Code? I make changes to a file and run, but it ignores my breakpoints.

First, how to I integrate the clock with the Map/Terrain/Pathfinding subsystem? I don't just want to start passing the clock through everything, but it seems like, with this task, as well as the Cost Stamp and Record History issues, time will be needed in the pathfinding system. How will this be integrated?

Where would you need to pass the clock? You very likely only need to pass the time value but the clock is not necessary IMO.

Also, would it be good practice to include non-time based overrides for CostField set_cost which simply set the time to TIME_ZERO for initialization? I have done this for the CostField function that is used by the Map class, but only to avoid needing to pass in a time_t from the map.

That would kind of counteract introducing dirty flags, so I'm not sure if this is a good idea. In fact, I'm not really sure why we should just always pass a time. Initialization does not always happen at time zero.

Lastly, how do I run with debugging using Visual Studio Code? I make changes to a file and run, but it ignores my breakpoints.

It should just work out of the box. What is your start configuration and output?

First, how to I integrate the clock with the Map/Terrain/Pathfinding subsystem? I don't just want to start passing the clock through everything, but it seems like, with this task, as well as the Cost Stamp and Record History issues, time will be needed in the pathfinding system. How will this be integrated?

Where would you need to pass the clock? You very likely only need to pass the time value but the clock is not necessary IMO.

Perhaps that's a better question. How to get the time (or any time) into the Map subsystem.

Perhaps that's a better question. How to get the time (or any time) into the Map subsystem.

The update time comes from events in the event system that will trigger a map update. However, I wouldn't worry about that right now, since it is not implemented yet.

It should just work out of the box. What is your start configuration and output?

If you are talking about the configurations in launch.json, it says:
"configurations": []

That's probably my problem lol. What should it say?

Something like this should work as a configuration:

{
    "name": "Main",
    "type": "cppdbg",
    "request": "launch",
    "cwd": "${workspaceFolder}/bin",
    "program": "${workspaceFolder}/bin/run",
    "args": [
        "main",
        "--verbose",
        "--gl-debug",
    ],
    "setupCommands": [
        {
            "description": "Enable pretty-printing for gdb",
            "text": "-enable-pretty-printing",
            "ignoreFailures": true
        },
        {
            "text": "source ${workspaceFolder}/etc/openage.gdbinit"
        }
    ],
}

Something like this should work as a configuration:

{
    "name": "Main",
    "type": "cppdbg",
    "request": "launch",
    "cwd": "${workspaceFolder}/bin",
    "program": "${workspaceFolder}/bin/run",
    "args": [
        "main",
        "--verbose",
        "--gl-debug",
    ],
    "setupCommands": [
        {
            "description": "Enable pretty-printing for gdb",
            "text": "-enable-pretty-printing",
            "ignoreFailures": true
        },
        {
            "text": "source ${workspaceFolder}/etc/openage.gdbinit"
        }
    ],
}

So to clarify, I should put this in launch.json? I am used to Visual Studio with C#.

You should put it in the configurations array, yes.

You should put it in the configurations array, yes.

[workspace]/bin/run does not exist

Well, you need to build the project before running :D

https://github.com/SFTtech/openage/blob/master/doc/building.md has info on the build procedure.