Add confetti burst after suggestion submit

wwwroot/app.js

@@ -511,11 +511,12 @@ function setupHandlers() {
         await api.createSuggestion(data);
         form.reset();
         toast(t("toast.suggestionAdded"));
+        triggerCelebration(form.querySelector("button[type=submit]"));
         await loadSuggestData();
     } catch (err) {
         toast(err.message, true);
     }
-    });
+});
 
     $("set-phase").addEventListener("click", async () => {
         const phase = $("phase-select").value;
@@ -874,6 +875,117 @@ function setupBackgroundPan(config = {}) {
     step();
 }
 
+// Celebration FX -----------------------------------------------------
+let fxCanvas;
+let fxCtx;
+let fxParticles = [];
+let fxAnimating = false;
+
+function ensureFxCanvas() {
+    if (fxCanvas) return;
+    fxCanvas = document.createElement("canvas");
+    fxCanvas.className = "fx-canvas";
+    fxCanvas.style.position = "fixed";
+    fxCanvas.style.inset = "0";
+    fxCanvas.style.pointerEvents = "none";
+    fxCanvas.style.zIndex = "120";
+    fxCanvas.width = window.innerWidth;
+    fxCanvas.height = window.innerHeight;
+    fxCtx = fxCanvas.getContext("2d");
+    document.body.appendChild(fxCanvas);
+    window.addEventListener("resize", () => {
+        fxCanvas.width = window.innerWidth;
+        fxCanvas.height = window.innerHeight;
+    });
+}
+
+function triggerCelebration(button) {
+    ensureFxCanvas();
+    const rect = (button || document.body).getBoundingClientRect();
+    const x = rect.left + rect.width / 2;
+    const y = rect.top + rect.height / 2;
+    spawnConfetti(x, y, 80);
+    spawnFirework(x, y, 40);
+    if (!fxAnimating) {
+        fxAnimating = true;
+        requestAnimationFrame(fxStep);
+    }
+}
+
+function spawnConfetti(x, y, count) {
+    for (let i = 0; i < count; i++) {
+        fxParticles.push({
+            x,
+            y,
+            vx: (Math.random() - 0.5) * 6,
+            vy: Math.random() * -6 - 2,
+            size: 6 + Math.random() * 4,
+            life: 60 + Math.random() * 20,
+            color: randomColor(),
+            type: "confetti",
+            wobble: Math.random() * Math.PI * 2,
+        });
+    }
+}
+
+function spawnFirework(x, y, count) {
+    for (let i = 0; i < count; i++) {
+        const angle = (Math.PI * 2 * i) / count + Math.random() * 0.3;
+        const speed = 3 + Math.random() * 3;
+        fxParticles.push({
+            x,
+            y,
+            vx: Math.cos(angle) * speed,
+            vy: Math.sin(angle) * speed,
+            size: 4 + Math.random() * 3,
+            life: 50 + Math.random() * 20,
+            color: randomColor(),
+            type: "spark",
+        });
+    }
+}
+
+function fxStep() {
+    if (!fxCtx || !fxCanvas) return;
+    fxCtx.clearRect(0, 0, fxCanvas.width, fxCanvas.height);
+    fxParticles = fxParticles.filter((p) => p.life > 0);
+    for (const p of fxParticles) {
+        if (p.type === "confetti") {
+            p.vy += 0.18;
+            p.vx *= 0.99;
+            p.wobble += 0.2;
+            p.x += p.vx + Math.cos(p.wobble) * 0.8;
+            p.y += p.vy;
+        } else {
+            p.vy += 0.08;
+            p.vx *= 0.995;
+            p.x += p.vx;
+            p.y += p.vy;
+        }
+        p.life -= 1;
+        fxCtx.fillStyle = p.color;
+        fxCtx.beginPath();
+        if (p.type === "confetti") {
+            fxCtx.fillRect(p.x, p.y, p.size, p.size * 0.6);
+        } else {
+            fxCtx.arc(p.x, p.y, p.size * 0.5, 0, Math.PI * 2);
+            fxCtx.fill();
+        }
+    }
+    if (fxParticles.length > 0) {
+        requestAnimationFrame(fxStep);
+    } else {
+        fxCtx.clearRect(0, 0, fxCanvas.width, fxCanvas.height);
+        fxAnimating = false;
+    }
+}
+
+function randomColor() {
+    const palette = ["#ff595e", "#ffca3a", "#8ac926", "#1982c4", "#6a4c93"];
+    return palette[Math.floor(Math.random() * palette.length)];
+}
+// -------------------------------------------------------------------
+
 async function main() {
     setupHandlers();
     try {