feat: CI creates Gitea releases with changelog, app polls for updates on startup

- android-build.yml: fetch full history+tags, embed VITE_APP_BUILD, add step
  to create a tagged Gitea release (build-N) with markdown changelog and APK
  release assets after every push; bump permissions to contents:write
- src/game/update-check.ts: polls Gitea releases/latest, compares build-N tag
  against CURRENT_BUILD (0 in dev), returns UpdateInfo or null; dismissal
  persisted to localStorage
- src/vite-env.d.ts: TypeScript env declarations for VITE_APP_BUILD
- src/scenes/MenuScene.ts: fire-and-forget update check on menu load; renders
  dismissible bottom-bar banner with optional APK download link
- src/game/ai.ts: early-game empty-table dump heuristic (safest card first)

src/scenes/MenuScene.ts

@@ -1,6 +1,7 @@
 import Phaser from 'phaser';
 import { Difficulty } from '../game/types';
 import { GameSceneData, loadAudioPreferences } from '../game/preferences';
+import { checkForUpdate, isDismissed, dismissUpdate, CURRENT_BUILD, UpdateInfo } from '../game/update-check';
 
 type MenuButtonPalette = {
   base: number;
@@ -133,6 +134,14 @@ export class MenuScene extends Phaser.Scene {
 
     this.createRulesPanel(layout);
     this.createControlPanel(layout, audioPreferences);
+
+    // Fire-and-forget update check — shows a dismissible banner if a newer
+    // CI build is available on Gitea.
+    checkForUpdate(CURRENT_BUILD).then(info => {
+      if (info && !isDismissed(info.buildNumber) && this.scene.isActive()) {
+        this.showUpdateBanner(layout, info);
+      }
+    }).catch(() => { /* network unavailable — silent */ });
   }
 
   private createLayout(width: number, height: number): MenuLayout {
@@ -576,4 +585,64 @@ export class MenuScene extends Phaser.Scene {
       this.scene.start('SettingsScene', { returnSceneKey: 'MenuScene' });
     });
   }
+
+  /**
+   * Renders a slim dismissible notification bar at the bottom of the visible
+   * area when a newer CI build is available on Gitea.
+   *
+   * Layout: [  "Aggiornamento disponibile — build N"  |  Scarica →  |  ✕  ]
+   */
+  private showUpdateBanner(layout: MenuLayout, info: UpdateInfo): void {
+    const bannerH = layout.isCompactViewport ? 40 : 48;
+    const bannerW = layout.visibleBounds.width - layout.frameInset * 2;
+    const cx = layout.visibleBounds.centerX;
+    // Float the banner along the very bottom edge of the visible area.
+    const cy = layout.visibleBounds.bottom - bannerH / 2 - 4;
+    const fs = layout.isCompactViewport ? 13 : 15;
+    const depth = 200;
+
+    // Collect all objects so the dismiss handler can destroy them together.
+    const objs: Phaser.GameObjects.GameObject[] = [];
+    const track = <T extends Phaser.GameObjects.GameObject>(o: T): T => {
+      objs.push(o); return o;
+    };
+
+    track(
+      this.add.rectangle(cx, cy, bannerW, bannerH, 0x0a1e3a, 0.96)
+        .setStrokeStyle(1, 0x4a90d9, 0.85)
+        .setDepth(depth),
+    );
+
+    track(
+      this.add.text(cx - bannerW / 2 + 12, cy,
+        `Aggiornamento disponibile — build ${info.buildNumber}`,
+        { fontFamily: 'Georgia, serif', fontSize: `${fs}px`, color: '#b8d8f8', resolution: 2 },
+      ).setOrigin(0, 0.5).setDepth(depth + 1),
+    );
+
+    // Dismiss (✕) — always present, rightmost.
+    const dismissBtn = track(
+      this.add.text(cx + bannerW / 2 - 12, cy, '✕', {
+        fontFamily: 'Georgia, serif', fontSize: `${fs + 4}px`, color: '#7a8a9a', resolution: 2,
+      }).setOrigin(1, 0.5).setDepth(depth + 1).setInteractive({ useHandCursor: true }),
+    ) as Phaser.GameObjects.Text;
+    dismissBtn.on('pointerover', () => dismissBtn.setColor('#c0d0e0'));
+    dismissBtn.on('pointerout', () => dismissBtn.setColor('#7a8a9a'));
+    dismissBtn.on('pointerdown', () => {
+      dismissUpdate(info.buildNumber);
+      objs.forEach(o => o.destroy());
+    });
+
+    // "Scarica →" link — present when a direct APK URL is available.
+    if (info.apkUrl) {
+      const dlBtn = track(
+        this.add.text(cx + bannerW / 2 - 38, cy, 'Scarica →', {
+          fontFamily: 'Georgia, serif', fontSize: `${fs}px`, color: '#5ba3e8', resolution: 2,
+        }).setOrigin(1, 0.5).setDepth(depth + 1).setInteractive({ useHandCursor: true }),
+      ) as Phaser.GameObjects.Text;
+      dlBtn.on('pointerover', () => dlBtn.setColor('#90c8ff'));
+      dlBtn.on('pointerout', () => dlBtn.setColor('#5ba3e8'));
+      dlBtn.on('pointerdown', () => window.open(info.apkUrl!, '_blank'));
+    }
+  }
 }