Add default auto approve rule for sed

[Tyriar]

Fixes #282209

[Copilot]

Pull request overview

This PR adds default auto-approve rules for the sed command to the terminal chat agent tools configuration. The implementation follows the established pattern of allowing safe sed commands while blocking potentially dangerous operations that could modify files or execute arbitrary code.

Key Changes

• Added auto-approve rules for the sed command with specific patterns to block dangerous flags and operations
• Added comprehensive test coverage for both allowed and blocked sed command variations

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 4 comments.

File	Description
src/vs/workbench/contrib/terminalContrib/chatAgentTools/common/terminalChatAgentToolsConfiguration.ts	Added sed command to auto-approve configuration with two regex patterns: one blocking dangerous flags (-i, -e, -f, and their long-form equivalents) and another blocking dangerous sed commands (/e, /w, ;W)
src/vs/workbench/contrib/terminalContrib/chatAgentTools/test/electron-browser/runInTerminalTool.test.ts	Added test cases for auto-approved sed commands (simple substitutions) and confirmation-required sed commands (in-place edits, file-based scripts, and dangerous command flags)