Add directory creation for copilot engine --add-dir paths

[Copilot]

Summary

The copilot engine now automatically creates all directories specified in --add-dir arguments before executing the copilot CLI. This prevents potential errors when the copilot CLI attempts to access directories that don't exist yet.

Problem

The copilot engine builds a list of --add-dir arguments that point to various directories:

• Default directories: /tmp/, /tmp/gh-aw/, /tmp/gh-aw/agent/
• Log directory: /tmp/gh-aw/.copilot/logs/
• Cache-memory directories (when configured): /tmp/gh-aw/cache-memory/, /tmp/gh-aw/cache-memory-{id}/
• Custom directories from engine args

However, these directories were not being created before invoking the copilot CLI, which could cause failures if the directories don't exist.

Solution

Added a helper function extractAddDirPaths that:

1. Scans all copilot arguments after they're fully assembled
2. Extracts directory paths following --add-dir flags
3. Includes the log directory (--log-dir) in the list
4. Generates mkdir -p commands for all directories
5. Inserts these commands before the copilot CLI invocation

Example Generated Output

set -o pipefail
COPILOT_CLI_INSTRUCTION=$(cat /tmp/gh-aw/aw-prompts/prompt.txt)
mkdir -p /tmp/
mkdir -p /tmp/gh-aw/
mkdir -p /tmp/gh-aw/agent/
mkdir -p /tmp/gh-aw/.copilot/logs/
copilot --add-dir /tmp/ --add-dir /tmp/gh-aw/ --add-dir /tmp/gh-aw/agent/ --log-level all --log-dir /tmp/gh-aw/.copilot/logs/ ...

Testing

Added comprehensive unit tests covering:

• Helper function with various argument patterns
• Default directory creation
• Cache-memory directory creation (multiple cache instances)
• Custom --add-dir paths from engine configuration

All existing tests continue to pass, confirming backward compatibility.

Fixes

Resolves the issue where copilot CLI could fail if directories specified in --add-dir arguments don't exist at runtime.

Original prompt

The copilot engine should review the --add-dir folders used in the args list and make sure those folders exist before running the cli.

Emit "mkdir -p ..." to prepare those directories.

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[pelikhan]

@copilot add safe output create issue staged to dev.md

[github-actions]

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