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_linkedin_accounts.sql

@@ -0,0 +1,68 @@
+-- Migration: Add LinkedIn accounts for auto-posting
+-- Description: Allows employees to link their LinkedIn accounts for automatic post publishing
+
+CREATE TABLE IF NOT EXISTS linkedin_accounts (
+    id UUID PRIMARY KEY DEFAULT uuid_generate_v4(),
+    user_id UUID NOT NULL REFERENCES auth.users(id) ON DELETE CASCADE,
+    created_at TIMESTAMP WITH TIME ZONE DEFAULT NOW(),
+    updated_at TIMESTAMP WITH TIME ZONE DEFAULT NOW(),
+
+    -- LinkedIn Identity
+    linkedin_user_id TEXT NOT NULL,
+    linkedin_vanity_name TEXT,
+    linkedin_name TEXT,
+    linkedin_picture TEXT,
+
+    -- OAuth Tokens (encrypted)
+    access_token TEXT NOT NULL,
+    refresh_token TEXT,
+    token_expires_at TIMESTAMP WITH TIME ZONE NOT NULL,
+    granted_scopes TEXT[] DEFAULT '{}',
+
+    -- Status
+    is_active BOOLEAN DEFAULT TRUE,
+    last_used_at TIMESTAMP WITH TIME ZONE,
+    last_error TEXT,
+    last_error_at TIMESTAMP WITH TIME ZONE,
+
+    UNIQUE(user_id)  -- Only one account per user
+);
+
+CREATE INDEX idx_linkedin_accounts_user_id ON linkedin_accounts(user_id);
+
+-- Enable RLS
+ALTER TABLE linkedin_accounts ENABLE ROW LEVEL SECURITY;
+
+-- Policy: Users can only see their own LinkedIn account
+CREATE POLICY "Users can view own linkedin account"
+    ON linkedin_accounts FOR SELECT
+    USING (auth.uid() = user_id);
+
+-- Policy: Users can insert their own LinkedIn account
+CREATE POLICY "Users can insert own linkedin account"
+    ON linkedin_accounts FOR INSERT
+    WITH CHECK (auth.uid() = user_id);
+
+-- Policy: Users can update their own LinkedIn account
+CREATE POLICY "Users can update own linkedin account"
+    ON linkedin_accounts FOR UPDATE
+    USING (auth.uid() = user_id);
+
+-- Policy: Users can delete their own LinkedIn account
+CREATE POLICY "Users can delete own linkedin account"
+    ON linkedin_accounts FOR DELETE
+    USING (auth.uid() = user_id);
+
+-- Function to update updated_at timestamp
+CREATE OR REPLACE FUNCTION update_linkedin_accounts_updated_at()
+RETURNS TRIGGER AS $$
+BEGIN
+    NEW.updated_at = NOW();
+    RETURN NEW;
+END;
+$$ LANGUAGE plpgsql;
+
+CREATE TRIGGER update_linkedin_accounts_updated_at
+    BEFORE UPDATE ON linkedin_accounts
+    FOR EACH ROW
+    EXECUTE FUNCTION update_linkedin_accounts_updated_at();