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>

config/migrate_add_license_system.sql

@@ -0,0 +1,94 @@
+-- Migration: Add License Key System with Company Limits
+-- This migration adds:
+-- 1. license_keys table for managing license keys
+-- 2. company_daily_quotas table for tracking daily usage
+-- 3. license_key_id reference in companies table
+
+-- ==================== LICENSE KEYS TABLE ====================
+
+CREATE TABLE IF NOT EXISTS license_keys (
+    id UUID PRIMARY KEY DEFAULT uuid_generate_v4(),
+    key TEXT UNIQUE NOT NULL,
+    description TEXT,
+
+    -- Limits (stored here, NOT in companies table)
+    max_employees INT NOT NULL DEFAULT 5,
+    max_posts_per_day INT NOT NULL DEFAULT 10,
+    max_researches_per_day INT NOT NULL DEFAULT 5,
+
+    -- Usage tracking
+    used BOOLEAN DEFAULT FALSE,
+    company_id UUID REFERENCES companies(id) ON DELETE SET NULL,
+    used_at TIMESTAMP WITH TIME ZONE,
+
+    created_at TIMESTAMP WITH TIME ZONE DEFAULT NOW(),
+    updated_at TIMESTAMP WITH TIME ZONE DEFAULT NOW()
+);
+
+-- Index for fast lookups
+CREATE INDEX IF NOT EXISTS idx_license_keys_key ON license_keys(key);
+CREATE INDEX IF NOT EXISTS idx_license_keys_used ON license_keys(used);
+CREATE INDEX IF NOT EXISTS idx_license_keys_company_id ON license_keys(company_id);
+
+-- RLS Policies (Admin only)
+ALTER TABLE license_keys ENABLE ROW LEVEL SECURITY;
+
+CREATE POLICY "Service role has full access to license_keys"
+    ON license_keys FOR ALL
+    USING (auth.jwt()->>'role' = 'service_role');
+
+-- ==================== EXTEND COMPANIES TABLE ====================
+
+-- Add license key reference to companies table
+-- (limits are stored in license_keys table, not duplicated here)
+ALTER TABLE companies ADD COLUMN IF NOT EXISTS license_key_id UUID REFERENCES license_keys(id);
+
+-- Index
+CREATE INDEX IF NOT EXISTS idx_companies_license_key_id ON companies(license_key_id);
+
+-- ==================== COMPANY DAILY QUOTAS TABLE ====================
+
+-- Track daily usage per company
+CREATE TABLE IF NOT EXISTS company_daily_quotas (
+    id UUID PRIMARY KEY DEFAULT uuid_generate_v4(),
+    company_id UUID NOT NULL REFERENCES companies(id) ON DELETE CASCADE,
+    date DATE NOT NULL,
+    posts_created INT DEFAULT 0,
+    researches_created INT DEFAULT 0,
+    created_at TIMESTAMP WITH TIME ZONE DEFAULT NOW(),
+    updated_at TIMESTAMP WITH TIME ZONE DEFAULT NOW(),
+
+    UNIQUE(company_id, date)
+);
+
+-- Index for fast daily lookups
+CREATE INDEX IF NOT EXISTS idx_company_daily_quotas_company_date ON company_daily_quotas(company_id, date);
+
+-- RLS Policies
+ALTER TABLE company_daily_quotas ENABLE ROW LEVEL SECURITY;
+
+CREATE POLICY "Users can view own company quotas"
+    ON company_daily_quotas FOR SELECT
+    USING (
+        company_id IN (
+            SELECT company_id FROM profiles WHERE id = auth.uid()
+        )
+    );
+
+CREATE POLICY "Service role has full access to company_daily_quotas"
+    ON company_daily_quotas FOR ALL
+    USING (auth.jwt()->>'role' = 'service_role');
+
+-- ==================== TRIGGERS ====================
+
+DROP TRIGGER IF EXISTS update_license_keys_updated_at ON license_keys;
+CREATE TRIGGER update_license_keys_updated_at
+    BEFORE UPDATE ON license_keys
+    FOR EACH ROW
+    EXECUTE FUNCTION update_updated_at_column();
+
+DROP TRIGGER IF EXISTS update_company_daily_quotas_updated_at ON company_daily_quotas;
+CREATE TRIGGER update_company_daily_quotas_updated_at
+    BEFORE UPDATE ON company_daily_quotas
+    FOR EACH ROW
+    EXECUTE FUNCTION update_updated_at_column();