Fix CameraEntropy video initialization and add stats review panel

- Fix videoRef timing issue by using useEffect for video setup
- Stop animation loop on capture to prevent infinite warnings
- Fix null canvas reference in generateMnemonicFromEntropy
- Add stats review panel with continue/retake options
- Add seed generation explanation and blurred preview
- Implement seed generation from camera noise/entropy bits and enhance dice rolls with detailed statistical analysis

src/lib/interactionEntropy.ts

@@ -0,0 +1,73 @@
+/**
+ * Collects entropy from user interactions (mouse, keyboard, touch)
+ * Runs in background to enhance any entropy generation method
+ */
+export class InteractionEntropy {
+    private samples: number[] = [];
+    private lastEvent = 0;
+    private startTime = performance.now();
+    private sources = { mouse: 0, keyboard: 0, touch: 0 };
+
+    constructor() {
+        this.initListeners();
+    }
+
+    private initListeners() {
+        const handleEvent = (e: MouseEvent | KeyboardEvent | TouchEvent) => {
+            const now = performance.now();
+            const delta = now - this.lastEvent;
+
+            if (delta > 0 && delta < 10000) { // Ignore huge gaps
+                this.samples.push(delta);
+
+                if (e instanceof MouseEvent) {
+                    this.samples.push(e.clientX ^ e.clientY);
+                    this.sources.mouse++;
+                } else if (e instanceof KeyboardEvent) {
+                    this.samples.push(e.key.codePointAt(0) ?? 0);
+                    this.sources.keyboard++;
+                } else if (e instanceof TouchEvent && e.touches[0]) {
+                    this.samples.push(e.touches[0].clientX ^ e.touches[0].clientY);
+                    this.sources.touch++;
+                }
+            }
+            this.lastEvent = now;
+
+            // Keep last 256 samples (128 pairs)
+            if (this.samples.length > 256) {
+                this.samples.splice(0, this.samples.length - 256);
+            }
+        };
+
+        document.addEventListener('mousemove', handleEvent);
+        document.addEventListener('keydown', handleEvent);
+        document.addEventListener('touchmove', handleEvent);
+    }
+
+    async getEntropyBytes(): Promise<Uint8Array> {
+        // Convert samples to entropy via SHA-256
+        const data = new TextEncoder().encode(
+            this.samples.join(',') + performance.now()
+        );
+        const hash = await crypto.subtle.digest('SHA-256', data);
+        return new Uint8Array(hash);
+    }
+
+    getSampleCount(): { mouse: number; keyboard: number; touch: number; total: number } {
+        return {
+            ...this.sources,
+            total: this.sources.mouse + this.sources.keyboard + this.sources.touch
+        };
+    }
+
+    getCollectionTime(): number {
+        return performance.now() - this.startTime;
+    }
+
+    clear() {
+        this.samples = [];
+        this.lastEvent = 0;
+        this.startTime = performance.now();
+        this.sources = { mouse: 0, keyboard: 0, touch: 0 };
+    }
+}