Remove customize appearance and learning improvement bullets

- Removed chat:write.customize scope explanation per feedback
- Removed custom appearance reference from permissions rationale
- Removed AI learning/improvement explanation per feedback

Author: codegen-sh[bot]

docs/integrations/slack.mdx

@@ -91,7 +91,6 @@ The Codegen Slack integration requires the following permissions to function eff
 - **Send messages** - To communicate responses and provide updates
 
 ### Enhanced Communication Features
-- **Customize message appearance** (`chat:write.customize`) - Allows Codegen to post messages with custom usernames and avatars when representing different contexts or providing specialized responses (e.g., when acting as a specific type of assistant or when providing updates from different integrated services)
 - **View and react with emojis** - To acknowledge messages and provide feedback through reactions
 
 ### User and Workspace Access
@@ -102,7 +101,6 @@ The Codegen Slack integration requires the following permissions to function eff
 ### Why These Permissions Are Necessary
 
 - **Email mapping** enables secure account linking between Slack and Codegen, ensuring proper access control
-- **Custom appearance** allows for clearer communication when Codegen is providing updates from different integrated services
 - **Group DM access** ensures Codegen can participate in team discussions and collaborative planning sessions
 
 ## Data Privacy and Security
@@ -135,7 +133,6 @@ Codegen uses artificial intelligence to provide intelligent code assistance, aut
 
 - **Message Analysis:** Your Slack messages are processed by AI models to understand intent and generate appropriate responses
 - **Code Context:** When working with repositories, AI models analyze relevant code to provide accurate assistance
-- **Learning and Improvement:** AI interactions help improve response quality, but no personal data is used for model training without explicit consent
 
 **AI Limitations:**