Tasks
* #3572267 Update provider matrix: Mistral now supports Embeddings and Moderation
* #3571220 Adjust Global AI CSS and Introduce new Icons
* #3574064 Show in the UI that an AI Agent is "Connected" to the Assistant

Bugs
* #3574642 Fix composer.json in 1.2.x-dev
* #3574457 Remove ECA dev dependency from  AI module
* #3558536 Unclosed resource in \Drupal\ai\Base\OpenAiBasedProviderClientBase::speechToText()
* #3552530 AI Provider Documentation Example - Cleanup ConfigForm Example
* #3538762 FWA plugin error: Call to a member function get() on array
* #3571092 InvalidArgumentException when selecting a tool in the Tools Explorer which has an array property with default value
* #3572765 Regression: setting a parameter empty class breaks certain models in LiteLLM
* #3571925 Output streaming is handled inconsistently, fails to work in API AI-explorer

Contributors:
fago, robloach, marcus_johansson, kristen pol, petar_basic, scott_euser, mxr576, anmolgoyal74, stefan.korn, bisonbleu, anjaliprasannan, rob_e, prabha1997, bbruno, danrod, erichomanchuk, narendrar, brunocarvalho, yautja_cetanu, scott falconer, arianraeesi