Enable strictNullChecks, eqeqeq (#436)

## Description:

Improve type safety and runtime correctness by:
1. Enabling TypeScript's
[strictNullChecks](https://www.typescriptlang.org/tsconfig/#strictNullChecks)
compiler option.
2. Replacing all loose equality operators (`==` and `!=`) with strict
equality operators (`===` and `!==`).
3. Cleaning up of type declarations, null handling logic, and equality
expressions throughout the project.

Currently, the code allows implicit assumptions that `null` and
`undefined` are interchangeable, and relies on type-coercing equality
checks that can introduce subtle bugs. These practices make it difficult
to reason about when values may be absent and hinder the effectiveness
of static analysis.

Migrating to strict null checks and enforcing strict equality
comparisons will clarify intent, reduce bugs, and make the codebase
safer and easier to maintain.

Fixes #466 

## Please complete the following:

- [x] I have added screenshots for all UI updates
- [x] I confirm I have thoroughly tested these changes and take full
responsibility for any bugs introduced
- [x] I understand that submitting code with bugs that could have been
caught through manual testing blocks releases and new features for all
contributors

---------

Co-authored-by: Scott Anderson <662325+scottanderson@users.noreply.github.com>
Co-authored-by: evanpelle <openfrontio@gmail.com>

src/core/execution/alliance/AllianceRequestExecution.ts

@@ -3,9 +3,8 @@ import { Execution, Game, Player, PlayerID } from "../../game/Game";
 
 export class AllianceRequestExecution implements Execution {
   private active = true;
-  private mg: Game = null;
-  private requestor: Player;
-  private recipient: Player;
+  private requestor: Player | null = null;
+  private recipient: Player | null = null;
 
   constructor(
     private requestorID: PlayerID,
@@ -28,12 +27,14 @@ export class AllianceRequestExecution implements Execution {
       return;
     }
 
-    this.mg = mg;
     this.requestor = mg.player(this.requestorID);
     this.recipient = mg.player(this.recipientID);
   }
 
   tick(ticks: number): void {
+    if (this.requestor === null || this.recipient === null) {
+      throw new Error("Not initialized");
+    }
     if (this.requestor.isFriendly(this.recipient)) {
       consolex.warn("already allied");
     } else if (!this.requestor.canSendAllianceRequest(this.recipient)) {
@@ -44,10 +45,6 @@ export class AllianceRequestExecution implements Execution {
     this.active = false;
   }
 
-  owner(): Player {
-    return null;
-  }
-
   isActive(): boolean {
     return this.active;
   }

src/core/execution/alliance/AllianceRequestReplyExecution.ts

@@ -3,9 +3,8 @@ import { Execution, Game, Player, PlayerID } from "../../game/Game";
 
 export class AllianceRequestReplyExecution implements Execution {
   private active = true;
-  private mg: Game = null;
-  private requestor: Player;
-  private recipient: Player;
+  private requestor: Player | null = null;
+  private recipient: Player | null = null;
 
   constructor(
     private requestorID: PlayerID,
@@ -28,19 +27,21 @@ export class AllianceRequestReplyExecution implements Execution {
       this.active = false;
       return;
     }
-    this.mg = mg;
     this.requestor = mg.player(this.requestorID);
     this.recipient = mg.player(this.recipientID);
   }
 
   tick(ticks: number): void {
+    if (this.requestor === null || this.recipient === null) {
+      throw new Error("Not initialized");
+    }
     if (this.requestor.isFriendly(this.recipient)) {
       consolex.warn("already allied");
     } else {
       const request = this.requestor
         .outgoingAllianceRequests()
-        .find((ar) => ar.recipient() == this.recipient);
-      if (request == null) {
+        .find((ar) => ar.recipient() === this.recipient);
+      if (request === undefined) {
         consolex.warn("no alliance request found");
       } else {
         if (this.accept) {
@@ -55,10 +56,6 @@ export class AllianceRequestReplyExecution implements Execution {
     this.active = false;
   }
 
-  owner(): Player {
-    return null;
-  }
-
   isActive(): boolean {
     return this.active;
   }

src/core/execution/alliance/BreakAllianceExecution.ts

@@ -3,9 +3,9 @@ import { Execution, Game, Player, PlayerID } from "../../game/Game";
 
 export class BreakAllianceExecution implements Execution {
   private active = true;
-  private requestor: Player;
-  private recipient: Player;
-  private mg: Game;
+  private requestor: Player | null = null;
+  private recipient: Player | null = null;
+  private mg: Game | null = null;
 
   constructor(
     private requestorID: PlayerID,
@@ -33,14 +33,21 @@ export class BreakAllianceExecution implements Execution {
   }
 
   tick(ticks: number): void {
+    if (
+      this.mg === null ||
+      this.requestor === null ||
+      this.recipient === null
+    ) {
+      throw new Error("Not initialized");
+    }
     const alliance = this.requestor.allianceWith(this.recipient);
-    if (alliance == null) {
+    if (alliance === null) {
       consolex.warn("cant break alliance, not allied");
     } else {
       this.requestor.breakAlliance(alliance);
       this.recipient.updateRelation(this.requestor, -200);
       for (const player of this.mg.players()) {
-        if (player != this.requestor) {
+        if (player !== this.requestor) {
           player.updateRelation(this.requestor, -40);
         }
       }
@@ -48,10 +55,6 @@ export class BreakAllianceExecution implements Execution {
     this.active = false;
   }
 
-  owner(): Player {
-    return null;
-  }
-
   isActive(): boolean {
     return this.active;
   }