feat/ai-adapter

[Aryan-Verma-999]

Pluggable AI Adapter Layer

Adds a zero-dependency @embeddedchat/ai-adapter package that lets host applications inject any LLM provider (Ollama, OpenAI, Gemini, or custom) into EmbeddedChat without adding AI dependencies to the core library.

Acceptance Criteria fulfillment

• New @embeddedchat/ai-adapter package with IAIAdapter interface, BaseAIAdapter base class, and adapter implementations for Ollama, OpenAI, and Gemini
• AI is entirely opt-in, passing no aiAdapter prop leaves the UI identical to today, zero footprint
• ✨ Reply suggestions - click to get 3 AI-generated reply chips above the input
• 📝 Chat summary - modal with a concise summary of the conversation

Video/Screenshots

2026-06-25.12-22-06.mp4

PR Test Details

Note: The PR will be ready for live testing at https://rocketchat.github.io/EmbeddedChat/pulls/pr-1334 after approval. Contributors are requested to replace <pr_number> with the actual PR number.