Add quiet/minimal display mode that hides tool call output

Summary

Add a third display verbosity level ("minimal" or "quiet") that hides tool call output entirely, showing only the agent's direct text communication and task checklists.

Current Behavior

Claude Code has two display states toggled via Ctrl+O (app:toggleTranscript):

1. Default (condensed) — tool names + truncated output
2. Verbose — full tool output

There is no way to go quieter than the default view.

Desired Behavior

A third display state — minimal/operator view — that:

• Shows only the agent's natural language text responses
• Shows task checklists and progress indicators
• Hides bash command output, file edit diffs, code snippets, and tool call details
• Is toggleable via the existing Ctrl+O cycle (three states) or a separate keybinding

Use Case

Operators who trust the agent's execution and care about outcomes, not implementation details. When reviewing a session, the interesting content is:

• What the agent decided to do and why
• Task progress (checklists)
• Results and summaries
• Questions requiring input

The tool call output (bash commands, file diffs, line edits) is noise for this user. They're evaluating the system as an end customer, not reviewing individual code changes.

Suggested Implementation

The app:toggleTranscript keybinding already cycles between two states. Adding a third state to the cycle would be architecturally minimal:

• Ctrl+O cycle: Minimal → Default → Verbose → Minimal
• Or: a separate keybinding action like app:toggleMinimalView
• Or: a setting like displayMode: "minimal" | "default" | "verbose"

Environment

• Claude Code CLI (terminal)
• Interactive mode (not -p print mode)