revert(captain): undo OpenAI provider switch (wrong scope)

The OpenAI Custom Server request targets the per-account OpenAI integration
(/app/accounts/{id}/settings/integrations/openai), not the instance-level
Captain config. The CAPTAIN_OPEN_AI_PROVIDER provider-switch added in 46fe70398
was out of the intended scope and is new behavior that did not previously exist,
so it is removed. This restores the original Captain behavior (CAPTAIN_OPEN_AI_ENDPOINT
remains usable as before, no provider gating). The correct implementation goes in
config/integration/apps.yml for the per-account openai integration.

app/controllers/super_admin/app_configs_controller.rb

@@ -56,7 +56,7 @@ class SuperAdmin::AppConfigsController < SuperAdmin::ApplicationController
       'whatsapp_embedded' => %w[WHATSAPP_APP_ID WHATSAPP_APP_SECRET WHATSAPP_CONFIGURATION_ID WHATSAPP_API_VERSION],
       'notion' => %w[NOTION_CLIENT_ID NOTION_CLIENT_SECRET],
       'google' => %w[GOOGLE_OAUTH_CLIENT_ID GOOGLE_OAUTH_CLIENT_SECRET GOOGLE_OAUTH_REDIRECT_URI ENABLE_GOOGLE_OAUTH_LOGIN],
-      'captain' => %w[CAPTAIN_OPEN_AI_PROVIDER CAPTAIN_OPEN_AI_API_KEY CAPTAIN_OPEN_AI_MODEL CAPTAIN_OPEN_AI_ENDPOINT]
+      'captain' => %w[CAPTAIN_OPEN_AI_API_KEY CAPTAIN_OPEN_AI_MODEL CAPTAIN_OPEN_AI_ENDPOINT]
     }
 
     @allowed_configs = mapping.fetch(@config, general_configs)

app/models/installation_config.rb

@@ -37,8 +37,6 @@ class InstallationConfig < ApplicationRecord
   before_validation :set_lock
   validates :name, presence: true
   validate :saml_sso_users_check, if: -> { name == 'ENABLE_SAML_SSO_LOGIN' }
-  validate :openai_custom_provider_check, if: -> { name == 'CAPTAIN_OPEN_AI_PROVIDER' }
-  validate :openai_custom_endpoint_check, if: -> { name == 'CAPTAIN_OPEN_AI_ENDPOINT' }
 
   # TODO: Get rid of default scope
   # https://stackoverflow.com/a/1834250/939299
@@ -73,28 +71,4 @@ class InstallationConfig < ApplicationRecord
 
     errors.add(:base, 'Cannot disable SAML SSO login while users are using SAML authentication')
   end
-
-  # Only allow provider values the platform understands ('openai' default or 'custom')
-  # and ensure the "custom" provider actually requires an endpoint.
-  def openai_custom_provider_check
-    return if %w[openai custom].include?(value.to_s)
-
-    errors.add(:base, 'CAPTAIN_OPEN_AI_PROVIDER must be "openai" or "custom"')
-  end
-
-  # Fail-closed: when the provider is "custom", CAPTAIN_OPEN_AI_ENDPOINT must be
-  # present AND a secure https URL (OpenAI-compatible base).
-  def openai_custom_endpoint_check
-    provider = InstallationConfig.find_by(name: 'CAPTAIN_OPEN_AI_PROVIDER')&.value.to_s
-    return unless provider == 'custom'
-
-    if value.blank?
-      errors.add(:base, 'CAPTAIN_OPEN_AI_ENDPOINT is required when using the custom provider')
-      return
-    end
-
-    return if value.to_s.match?(%r{\Ahttps://\S+})
-
-    errors.add(:base, 'CAPTAIN_OPEN_AI_ENDPOINT must be a valid https URL when using the custom provider')
-  end
 end

config/initializers/ai_agents.rb

@@ -5,7 +5,7 @@ require 'agents'
 Rails.application.config.after_initialize do
   api_key = InstallationConfig.find_by(name: 'CAPTAIN_OPEN_AI_API_KEY')&.value
   model = InstallationConfig.find_by(name: 'CAPTAIN_OPEN_AI_MODEL')&.value.presence || LlmConstants::DEFAULT_MODEL
-  api_endpoint = Llm::Config.openai_endpoint.presence || LlmConstants::OPENAI_API_ENDPOINT
+  api_endpoint = InstallationConfig.find_by(name: 'CAPTAIN_OPEN_AI_ENDPOINT')&.value || LlmConstants::OPENAI_API_ENDPOINT
 
   if api_key.present?
     Agents.configure do |config|

config/installation_config.yml

@@ -191,15 +191,6 @@
   display_title: 'OpenAI API Endpoint (optional)'
   description: 'The OpenAI endpoint configured for use in Captain AI. Default: https://api.openai.com/'
   locked: false
-- name: CAPTAIN_OPEN_AI_PROVIDER
-  display_title: 'OpenAI Provider'
-  description: 'Select the OpenAI-compatible provider: "openai" uses the default api.openai.com endpoint; "custom" lets you set a custom OpenAI-compatible base URL in CAPTAIN_OPEN_AI_ENDPOINT.'
-  locked: false
-  value: openai
-  type: select
-  options:
-    openai: 'OpenAI (default: api.openai.com)'
-    custom: 'OpenAI Custom Server'
 - name: CAPTAIN_EMBEDDING_MODEL
   display_title: 'Embedding Model (optional)'
   description: 'The embedding model configured for use in Captain AI. Default: text-embedding-3-small'

lib/captain/base_task_service.rb

@@ -32,7 +32,7 @@ class Captain::BaseTaskService
   end
 
   def api_base
-    endpoint = Llm::Config.openai_endpoint.presence || 'https://api.openai.com/'
+    endpoint = InstallationConfig.find_by(name: 'CAPTAIN_OPEN_AI_ENDPOINT')&.value.presence || 'https://api.openai.com/'
     endpoint = endpoint.chomp('/')
     "#{endpoint}/v1"
   end

lib/integrations/llm_base_service.rb

@@ -84,7 +84,7 @@ class Integrations::LlmBaseService
   end
 
   def api_base
-    endpoint = Llm::Config.openai_endpoint.presence || 'https://api.openai.com/'
+    endpoint = InstallationConfig.find_by(name: 'CAPTAIN_OPEN_AI_ENDPOINT')&.value.presence || 'https://api.openai.com/'
     endpoint = endpoint.chomp('/')
     "#{endpoint}/v1"
   end

lib/integrations/openai/key_validator.rb

@@ -20,7 +20,7 @@ module Integrations::Openai::KeyValidator
   end
 
   def self.api_base
-    endpoint = Llm::Config.openai_endpoint.presence || 'https://api.openai.com/'
+    endpoint = InstallationConfig.find_by(name: 'CAPTAIN_OPEN_AI_ENDPOINT')&.value.presence || 'https://api.openai.com/'
     "#{endpoint.chomp('/')}/v1"
   end
 end

lib/llm/config.rb

@@ -29,20 +29,6 @@ module Llm::Config
       yield context
     end
 
-    # Returns the OpenAI-compatible base URL for Captain AI.
-    # - provider == 'custom'  -> use the operator-configured CAPTAIN_OPEN_AI_ENDPOINT
-    # - provider == 'openai'  -> nil (RubyLLM uses the default https://api.openai.com/)
-    def openai_endpoint
-      provider = InstallationConfig.find_by(name: 'CAPTAIN_OPEN_AI_PROVIDER')&.value.presence || 'openai'
-      return nil unless provider == 'custom'
-
-      InstallationConfig.find_by(name: 'CAPTAIN_OPEN_AI_ENDPOINT')&.value
-    end
-
-    def system_api_key
-      InstallationConfig.find_by(name: 'CAPTAIN_OPEN_AI_API_KEY')&.value
-    end
-
     private
 
     def configure_ruby_llm
@@ -53,5 +39,13 @@ module Llm::Config
         config.logger = Rails.logger
       end
     end
+
+    def system_api_key
+      InstallationConfig.find_by(name: 'CAPTAIN_OPEN_AI_API_KEY')&.value
+    end
+
+    def openai_endpoint
+      InstallationConfig.find_by(name: 'CAPTAIN_OPEN_AI_ENDPOINT')&.value
+    end
   end
 end