feat: Implement unsubscribe link for marketing automation [31188f42]

This commit introduces a new unsubscribe feature to allow contacts to opt-out
from marketing automation.

Key changes include:
- Database schema migration: Added  (UUID) to the  model.
- Data population: Implemented a script to assign unique tokens to existing contacts.
- API endpoint: Created a public GET  endpoint to handle opt-out requests.
- Automation: New contacts automatically receive an unsubscribe token upon creation.
- Integration: The full unsubscribe link is now returned via the provisioning API
  for storage in SuperOffice UDFs (ProgID: SuperOffice:9).
- Documentation: Updated  and
  to reflect the new feature and its integration requirements.
- Added  for quick overview and next steps.

company-explorer/backend/scripts/add_unsubscribe_tokens.py

@@ -0,0 +1,44 @@
+import uuid
+import os
+import sys
+
+# This is the crucial part to fix the import error.
+# We add the 'company-explorer' directory to the path, so imports can be absolute
+# from the 'backend' module.
+sys.path.insert(0, os.path.abspath(os.path.join(os.path.dirname(__file__), '../..')))
+
+from backend.database import Contact, SessionLocal
+
+def migrate_existing_contacts():
+    """
+    Generates and adds an unsubscribe_token for all existing contacts
+    that do not have one yet.
+    """
+    db = SessionLocal()
+    try:
+        contacts_to_update = db.query(Contact).filter(Contact.unsubscribe_token == None).all()
+        
+        if not contacts_to_update:
+            print("All contacts already have an unsubscribe token. No migration needed.")
+            return
+
+        print(f"Found {len(contacts_to_update)} contacts without an unsubscribe token. Generating tokens...")
+
+        for contact in contacts_to_update:
+            token = str(uuid.uuid4())
+            contact.unsubscribe_token = token
+            print(f"  - Generated token for contact ID {contact.id} ({contact.email})")
+
+        db.commit()
+        print("\nSuccessfully updated all contacts with new unsubscribe tokens.")
+
+    except Exception as e:
+        print(f"An error occurred: {e}")
+        db.rollback()
+    finally:
+        db.close()
+
+if __name__ == "__main__":
+    print("Starting migration: Populating unsubscribe_token for existing contacts.")
+    migrate_existing_contacts()
+    print("Migration finished.")

company-explorer/backend/scripts/migrate_db.py

@@ -89,6 +89,17 @@ def migrate_tables():
         """)
         logger.info("Table 'reported_mistakes' ensured to exist.")
         
+        # 4. Update CONTACTS Table (Two-step for SQLite compatibility)
+        logger.info("Checking 'contacts' table schema for unsubscribe_token...")
+        contacts_columns = get_table_columns(cursor, "contacts")
+        
+        if 'unsubscribe_token' not in contacts_columns:
+            logger.info("Adding column 'unsubscribe_token' to 'contacts' table...")
+            cursor.execute("ALTER TABLE contacts ADD COLUMN unsubscribe_token TEXT")
+
+            logger.info("Creating UNIQUE index on 'unsubscribe_token' column...")
+            cursor.execute("CREATE UNIQUE INDEX IF NOT EXISTS idx_contacts_unsubscribe_token ON contacts (unsubscribe_token)")
+
         conn.commit()
         logger.info("All migrations completed successfully.")