feat: replace browser dialogs with in-game naming screen + notifications

Remove prompt() and alert() calls that broke game immersion. Add:
- Pokemon-style naming screen with character grid + direct typing
- Canvas-rendered notification toasts (with fade-out animation)
- Both render on top of workshop AND world mode canvases
- Workshop keyboard handler yields to naming screen when active

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

js/renderer.js

@@ -4,6 +4,7 @@ import { state } from './state.js';
 import { getInputPorts, getOutputPorts, getComponentWidth, getComponentHeight } from './gates.js';
 import { getGateLabel, drawWaveLabels, drawWaveforms } from './waveform.js';
 import { getBusPairs } from './bus.js';
+import { drawNamingScreen, drawNotification } from './world/inventory.js';
 
 let canvas, ctx;
 let circuitAnimFrameId = null;
@@ -663,5 +664,9 @@ function draw() {
         drawWaveforms();
     }
 
+    // In-game overlays (naming screen, notifications) — render on top
+    drawNamingScreen(ctx, canvas.width, canvas.height);
+    drawNotification(ctx, canvas.width);
+
     circuitAnimFrameId = requestAnimationFrame(draw);
 }