feat: Implementar PWA, Analytics, Reportes PDF y mejoras OCR

FASE 1 - PWA y Frontend:
- Crear templates/base.html, dashboard.html, analytics.html, executive.html
- Crear static/css/main.css con diseño responsivo
- Agregar static/js/app.js, pwa.js, camera.js, charts.js
- Implementar manifest.json y service-worker.js para PWA
- Soporte para captura de tickets desde cámara móvil

FASE 2 - Analytics:
- Crear módulo analytics/ con predictions.py, trends.py, comparisons.py
- Implementar predicción básica con promedio móvil + tendencia lineal
- Agregar endpoints /api/analytics/trends, predictions, comparisons
- Integrar Chart.js para gráficas interactivas

FASE 3 - Reportes PDF:
- Crear módulo reports/ con pdf_generator.py
- Implementar SalesReportPDF con generar_reporte_diario y ejecutivo
- Agregar comando /reporte [diario|semanal|ejecutivo]
- Agregar endpoints /api/reports/generate y /api/reports/download

FASE 4 - Mejoras OCR:
- Crear módulo ocr/ con processor.py, preprocessor.py, patterns.py
- Implementar AmountDetector con patrones múltiples de montos
- Agregar preprocesador adaptativo con pipelines para diferentes condiciones
- Soporte para corrección de rotación (deskew) y threshold Otsu

Dependencias agregadas:
- reportlab, matplotlib (PDF)
- scipy, pandas (analytics)
- imutils, deskew, cachetools (OCR)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

sales-bot/static/js/pwa.js

@@ -0,0 +1,122 @@
+/**
+ * Sales Bot - PWA Registration and Install Prompt
+ */
+
+// Register Service Worker
+if ('serviceWorker' in navigator) {
+    window.addEventListener('load', async () => {
+        try {
+            const registration = await navigator.serviceWorker.register('/service-worker.js');
+            console.log('Service Worker registered:', registration.scope);
+
+            // Check for updates
+            registration.addEventListener('updatefound', () => {
+                const newWorker = registration.installing;
+                newWorker.addEventListener('statechange', () => {
+                    if (newWorker.state === 'installed' && navigator.serviceWorker.controller) {
+                        // New version available
+                        showUpdatePrompt();
+                    }
+                });
+            });
+        } catch (error) {
+            console.error('Service Worker registration failed:', error);
+        }
+    });
+}
+
+// Install prompt handling
+let deferredPrompt;
+
+window.addEventListener('beforeinstallprompt', (e) => {
+    e.preventDefault();
+    deferredPrompt = e;
+    showInstallPrompt();
+});
+
+function showInstallPrompt() {
+    // Create install prompt UI
+    const prompt = document.createElement('div');
+    prompt.id = 'install-prompt';
+    prompt.className = 'install-prompt show';
+    prompt.innerHTML = `
+        <span>Instalar Sales Bot en tu dispositivo</span>
+        <button class="btn btn-primary" onclick="installPWA()">Instalar</button>
+        <button class="btn btn-secondary" onclick="dismissInstallPrompt()">Ahora no</button>
+    `;
+    document.body.appendChild(prompt);
+}
+
+async function installPWA() {
+    if (!deferredPrompt) return;
+
+    deferredPrompt.prompt();
+    const { outcome } = await deferredPrompt.userChoice;
+
+    console.log('Install prompt outcome:', outcome);
+    deferredPrompt = null;
+    dismissInstallPrompt();
+
+    if (outcome === 'accepted') {
+        if (window.Utils) {
+            window.Utils.showNotification('App instalada correctamente', 'success');
+        }
+    }
+}
+
+function dismissInstallPrompt() {
+    const prompt = document.getElementById('install-prompt');
+    if (prompt) {
+        prompt.remove();
+    }
+}
+
+function showUpdatePrompt() {
+    const updateBanner = document.createElement('div');
+    updateBanner.id = 'update-banner';
+    updateBanner.style.cssText = `
+        position: fixed;
+        bottom: 0;
+        left: 0;
+        right: 0;
+        background: #00d4ff;
+        color: #000;
+        padding: 15px;
+        text-align: center;
+        z-index: 9999;
+    `;
+    updateBanner.innerHTML = `
+        <span>Nueva version disponible</span>
+        <button onclick="updateApp()" style="margin-left: 15px; padding: 5px 15px; border: none; border-radius: 4px; cursor: pointer;">
+            Actualizar
+        </button>
+    `;
+    document.body.appendChild(updateBanner);
+}
+
+function updateApp() {
+    if ('serviceWorker' in navigator) {
+        navigator.serviceWorker.getRegistration().then(registration => {
+            if (registration && registration.waiting) {
+                registration.waiting.postMessage({ type: 'SKIP_WAITING' });
+            }
+        });
+    }
+    window.location.reload();
+}
+
+// Detect if running as PWA
+function isPWA() {
+    return window.matchMedia('(display-mode: standalone)').matches ||
+           window.navigator.standalone === true;
+}
+
+// Add PWA class to body if running as installed app
+if (isPWA()) {
+    document.body.classList.add('pwa-mode');
+}
+
+// Export
+window.installPWA = installPWA;
+window.dismissInstallPrompt = dismissInstallPrompt;
+window.isPWA = isPWA;