Add setting to disable in-session satisfaction survey

Request

Add a settings.json option (e.g., disableFeedbackSurvey: true) to suppress the periodic "How am I doing?" satisfaction survey that appears during sessions.

Motivation

During long, high-throughput interactive sessions (e.g., article review workflows with 40+ back-and-forth exchanges), the survey interrupts flow. The numbered response (1-5) can also be misinterpreted as input to the current task.

Power users who are satisfied and actively using Claude Code daily don't need periodic prompting. If they have feedback, they'll provide it proactively or via GitHub issues.

Suggested implementation

Either:

• A settings.json key: "disableFeedbackSurvey": true
• Or an env var: CLAUDE_CODE_DISABLE_FEEDBACK_SURVEY=1

Thank you!