Trading in lakes 🚤 (#3653)

## Description:

- Widened port placement and warship spawn/patrol checks from
`isOcean`/`isOceanShore` to `isWater`/`isShore`, so ports can be built
on lake shores and ships can operate on lakes, we discussed it here:

<img width="996" height="423" alt="image"
src="https://github.com/user-attachments/assets/acf1e970-9631-4848-a0ed-6d0470616e1d"
/>

- Filtered `tradingPorts()` by water component so ports only attempt
trades with reachable ports - prevents silent path-not-found failures
across disconnected water bodies
- Applied the same water component filter when a captured trade ship
reroutes to its new owner's nearest port
- Removed the `WaterManager` fallback that force-marked isolated
water-nuked-tiles as ocean (no longer needed since lakes are now
navigable)
- Added a check to prevent nations from building ports on water bodies
that aren't accessible to other players

## 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:

FloPinguin

---------

Co-authored-by: Evan <evanpelle@gmail.com>

src/core/execution/PortExecution.ts

@@ -97,10 +97,22 @@ export class PortExecution implements Execution {
   // It's a probability list, so if an element appears twice it's because it's
   // twice more likely to be picked later.
   tradingPorts(): Unit[] {
+    const sourceComponents = new Set<number>();
+    for (const neighbor of this.mg.neighbors(this.port!.tile())) {
+      if (!this.mg.isWater(neighbor)) continue;
+      const comp = this.mg.getWaterComponent(neighbor);
+      if (comp !== null) sourceComponents.add(comp);
+    }
     const ports = this.mg
       .players()
       .filter((p) => p !== this.port!.owner() && p.canTrade(this.port!.owner()))
       .flatMap((p) => p.units(UnitType.Port))
+      .filter((p) => {
+        for (const comp of sourceComponents) {
+          if (this.mg.hasWaterComponent(p.tile(), comp)) return true;
+        }
+        return false;
+      })
       .sort((p1, p2) => {
         return (
           this.mg.manhattanDist(this.port!.tile(), p1.tile()) -