feat: update all OpenAI/ChatGPT refs + settings dropdown for fixed-value fields

Co-authored-by: christianlouis <361235+christianlouis@users.noreply.github.com>

.env.demo

@@ -119,16 +119,44 @@ AUTHENTIK_CONFIG_URL=<ConfigUrlOfYourApp, e.g. https://authentik.example.com/app
 OAUTH_PROVIDER_NAME="Authentik SSO"
 
 # **AI/ML Services**
-# OpenAI
+# Select your AI provider: openai | azure | anthropic | gemini | ollama | openrouter | portkey | litellm
+AI_PROVIDER=openai
+# Model override (optional – falls back to OPENAI_MODEL when not set)
+# AI_MODEL=gpt-4o-mini
+
+# --- OpenAI (AI_PROVIDER=openai) ---
 OPENAI_API_KEY="<OPENAI_API_KEY>"
 OPENAI_BASE_URL=https://api.openai.com/v1
 OPENAI_MODEL=gpt-4o-mini
 
-# Azure AI
-AZURE_REGION="eastus"
-AZURE_ENDPOINT="https://<yourendpoint>.cognitiveservices.azure.com/"
-AZURE_AI_KEY=<AZURE_AI_KEY>
+# --- Anthropic Claude (AI_PROVIDER=anthropic) ---
+# ANTHROPIC_API_KEY=sk-ant-...
+# AI_MODEL=claude-3-5-sonnet-20241022
 
+# --- Google Gemini (AI_PROVIDER=gemini) ---
+# GEMINI_API_KEY=AIza...
+# AI_MODEL=gemini-1.5-pro
+
+# --- Ollama local LLMs (AI_PROVIDER=ollama) ---
+# OLLAMA_BASE_URL=http://localhost:11434
+# AI_MODEL=llama3.2
+
+# --- OpenRouter (AI_PROVIDER=openrouter) ---
+# OPENROUTER_API_KEY=sk-or-...
+# AI_MODEL=anthropic/claude-3.5-sonnet
+
+# --- Portkey AI Gateway (AI_PROVIDER=portkey) ---
+# PORTKEY_API_KEY=pk-...
+# PORTKEY_VIRTUAL_KEY=vk-...   # optional – routes to provider credentials in Portkey vault
+# PORTKEY_CONFIG=pc-...        # optional – saved Config ID for fallbacks / load balancing
+
+# --- Azure OpenAI (AI_PROVIDER=azure) ---
+# OPENAI_API_KEY=<azure-key>
+# OPENAI_BASE_URL=https://my-resource.openai.azure.com
+# AZURE_OPENAI_API_VERSION=2024-02-01
+# AI_MODEL=gpt-4o   # deployment name in Azure
+
+# Azure Document Intelligence (OCR – separate from AI provider above)
 # **Email Settings**
 EMAIL_HOST=smtp.example.com
 EMAIL_PORT=587