add some logs, fix frontend memory leak with users not deallocating their haku

closes #28

static/haku.js

@@ -130,6 +130,11 @@ export class Haku {
         w.haku_limits_destroy(pLimits);
     }
 
+    destroy() {
+        w.haku_brush_destroy(this.#pBrush);
+        w.haku_instance_destroy(this.#pInstance);
+    }
+
     setBrush(code) {
         w.haku_reset(this.#pInstance);
         // NOTE: Brush is invalid at this point, because we reset removes all defs and registered chunks.

static/online-users.js

@@ -15,6 +15,10 @@ export class User {
         this.painter = new Painter(wallInfo.paintArea);
     }
 
+    destroy() {
+        this.haku.destroy();
+    }
+
     setBrush(brush) {
         let compileResult = this.haku.setBrush(brush);
         this.isBrushOk = compileResult.status == "ok";
@@ -57,6 +61,7 @@ export class OnlineUsers extends EventTarget {
     removeUser(sessionId) {
         if (this.#users.has(sessionId)) {
             let user = this.#users.get(sessionId);
+            user.destroy();
             console.info("user removed", sessionId, user.nickname);
             // TODO: Cleanup reticles
             this.#users.delete(sessionId);