Map Generator Go Code Documentation (#2656)

Resolves #2602

## Description:
tldr: `npm run docs:map-generator`

Adds documentation to the `map-generator` go code.

This has no functional changes, other than the renaming of the package.
I used the github url, though this can be set to anything as long as it
contains a `.` so that the docs parse it correctly. Go doc best
practices seem a little verbose and terse, but attempted to comply

Future Facing (to get these docs viewable without running locally):
- Wait until the -http issue is sorted, then these are easy to
statically host alongside builds
- Could use the legacy `godoc`
- Could do formatting after outputting the `txt` output


## Change List:

- Add documentation to all types/fns in map-generator go code
- Ensure this outputs correctly with `go doc`
- Add `docs:map-generator` command to package.json. This runs `go doc`
in `map-generator` w/ appropriate flags to generate full documentation.
(see notes in readme)
- rename `map-generator` module to work around pkgsite assuming all
packages without a . are stdlib (this makes `-http` work at all)
- Add new sections to README and update existing sections
- Add additional references to locations in the primary code base where
things can be found
- Update documentation in the ts theme files to add output color
mappings - this ensures that everything needed to trace the input file
-> in game rendered asset is fully documented.


## Please complete the following:

- [X] I have added screenshots for all UI updates
- [X] I process any text displayed to the user through translateText()
and I've added it to the en.json file
- [X] I have added relevant tests to the test directory
- [X] I confirm I have thoroughly tested these changes and take full
responsibility for any bugs introduced

## Please put your Discord username so you can be contacted if a bug or
regression is found:

tidwell

src/core/configuration/PastelTheme.ts

@@ -138,6 +138,14 @@ export class PastelTheme implements Theme {
     return player.type() === PlayerType.Human ? "#000000" : "#4D4D4D";
   }
 
+  // | Terrain Type      | Magnitude | Base Color Logic                                | Visual Description                                                   |
+  // | :---------------- | :-------- | :---------------------------------------------- | :------------------------------------------------------------------- |
+  // | **Shore (Land)**  | N/A       | Fixed: `rgb(204, 203, 158)`                   | Sandy beige. Overrides other land types if adjacent to water.        |
+  // | **Plains**        | 0 - 9     | `rgb(190, 220, 138)` - `rgb(190, 202, 138)` | Light green. Gets slightly darker/less green as magnitude increases. |
+  // | **Highland**      | 10 - 19   | `rgb(220, 203, 158)` - `rgb(238, 221, 176)` | Tan/Beige. Gets lighter as magnitude increases.                      |
+  // | **Mountain**      | 20 - 30   | `rgb(240, 240, 240)` - `rgb(245, 245, 245)` | Grayscale (White/Grey). Represents snow caps or rocky peaks.         |
+  // | **Water (Shore)** | 0         | Fixed: `rgb(100, 143, 255)`                   | Light blue near land.                                                |
+  // | **Water (Deep)**  | 1 - 10+   | `rgb(70, 132, 180)` - `rgb(61, 123, 171)`   | Darker blue, adjusted slightly by distance to land.                  |
   terrainColor(gm: GameMap, tile: TileRef): Colord {
     const mag = gm.magnitude(tile);
     if (gm.isShore(tile)) {

src/core/configuration/PastelThemeDark.ts

@@ -9,6 +9,15 @@ export class PastelThemeDark extends PastelTheme {
   private darkWater = colord("rgb(14,11,30)");
   private darkShorelineWater = colord("rgb(50,50,50)");
 
+  // | Terrain Type      | Magnitude | Base Color Logic                                | Visual Description    |
+  // | :---------------- | :-------- | :---------------------------------------------- | :-------------------- |
+  // | **Shore (Land)**  | N/A       | Fixed: `rgb(134, 133, 88)`                    | Dark olive.           |
+  // | **Plains**        | 0 - 9     | `rgb(140, 170, 88)` - `rgb(140, 152, 88)`   | Muted green.          |
+  // | **Highland**      | 10 - 19   | `rgb(170, 153, 108)` - `rgb(188, 171, 126)` | Dark earth tone.      |
+  // | **Mountain**      | 20 - 30   | `rgb(190, 190, 190)` - `rgb(195, 195, 195)` | Dark gray.            |
+  // | **Water (Shore)** | 0         | Fixed: `rgb(50, 50, 50)`                      | Dark gray/black.      |
+  // | **Water (Deep)**  | 1 - 10+   | `rgb(22, 19, 38)` - `rgb(14, 11, 30)`       | Very dark blue/black. |
+
   terrainColor(gm: GameMap, tile: TileRef): Colord {
     const mag = gm.magnitude(tile);
     if (gm.isShore(tile)) {

src/core/game/GameMap.ts

@@ -249,6 +249,8 @@ export class GameMapImpl implements GameMap {
     return this.magnitude(ref) < 10 ? 2 : 1;
   }
 
+  // if updating these magnitude values, also update
+  // `../../../map-generator/map_generator.go` `getThumbnailColor`
   terrainType(ref: TileRef): TerrainType {
     if (this.isLand(ref)) {
       const magnitude = this.magnitude(ref);