## Overview
- document how to keep a per-user debug.json so global launch tasks show
up everywhere (Fixes #39849)
- sanitize REPL terminal text before copying so error blocks can be
copied and opened in buffers (Fixes #40207)

## Design Decisions
- reused the existing user debug file (paths::debug_scenarios_file) and
pointed docs at the zed::OpenDebugTasks command to stay aligned with the
settings UX
- extract a sanitize helper inside TerminalOutput::full_text to strip
\r/null padding while keeping indentation intact, then join the cleaned
lines so clipboard and buffers get readable text

## Testing
- Not run (cargo is unavailable in this environment)

Fixes #39849.
Fixes #40207.