The WGA today invited all franchised agents to apply to sign its proposed Code of Conduct, which bans agents from entering into packaging and production deals. The guild said the proposed Code, which is subject to ratification by its members on March 25, will go into effect after the April 6 expiration of its current agreement with the ATA. "We are continuing to talk to the agencies and any additional changes we agree to will be applied to all agencies," the guild said…