Major updates: LinkedIn auto-posting, timezone fixes, and Docker improvements

Features:
- Add LinkedIn OAuth integration and auto-posting functionality
- Add scheduler service for automated post publishing
- Add metadata field to generated_posts for LinkedIn URLs
- Add privacy policy page for LinkedIn API compliance
- Add company management features and employee accounts
- Add license key system for company registrations

Fixes:
- Fix timezone issues (use UTC consistently across app)
- Fix datetime serialization errors in database operations
- Fix scheduling timezone conversion (local time to UTC)
- Fix import errors (get_database -> db)

Infrastructure:
- Update Docker setup to use port 8001 (avoid conflicts)
- Add SSL support with nginx-proxy and Let's Encrypt
- Add LinkedIn setup documentation
- Add migration scripts for schema updates

Services:
- Add linkedin_service.py for LinkedIn API integration
- Add scheduler_service.py for background job processing
- Add storage_service.py for Supabase Storage
- Add email_service.py improvements
- Add encryption utilities for token storage

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

src/web/templates/research.html

@@ -13,7 +13,7 @@
         <form id="researchForm" class="card-bg rounded-xl border p-6">
             <div class="mb-6">
                 <label class="block text-sm font-medium text-gray-300 mb-2">Kunde auswählen</label>
-                <select name="customer_id" id="customerSelect" required class="w-full input-bg border rounded-lg px-4 py-3 text-white">
+                <select name="user_id" id="customerSelect" required class="w-full input-bg border rounded-lg px-4 py-3 text-white">
                     <option value="">-- Kunde wählen --</option>
                     {% for customer in customers %}
                     <option value="{{ customer.id }}">{{ customer.name }} - {{ customer.company_name or 'Kein Unternehmen' }}</option>
@@ -96,7 +96,7 @@ customerSelect.addEventListener('change', async () => {
     }
 
     try {
-        const response = await fetch(`/api/customers/${customerId}/post-types`);
+        const response = await fetch(`/api/users/${customerId}/post-types`);
         const data = await response.json();
 
         if (data.post_types && data.post_types.length > 0) {
@@ -150,7 +150,7 @@ form.addEventListener('submit', async (e) => {
     progressArea.classList.remove('hidden');
 
     const formData = new FormData();
-    formData.append('customer_id', customerId);
+    formData.append('user_id', customerId);
     if (selectedPostTypeId.value) {
         formData.append('post_type_id', selectedPostTypeId.value);
     }