v1.5.18

The image provider layer becomes a registry. Core no longer contains image-generation code.

Tiger_Agent_Provider_Factory::registerImageAdapter() matches the shape Tiger_Search::register() and Tiger_Audience::register() already use — a capability module registers its adapters at bootstrap and core holds the register, nothing more. canGenerateImages() and imageProviders() answer from the registry, so an install with no image module honestly reports no capability.

ImageAdapter gained supportsModel(), deleting core's static switch of model-name cues. Core knew which vendor models could draw, so every vendor release was a core edit.

generateImage() is gone from the OpenAI and Gemini adapters — core was shipping calls to endpoints it never used. The implementations live in TigerImage as subclasses, so transport, auth and the BYO key stay shared.

Needs TigerImage 0.2.0+. No effect on an install that does not generate images.