Bug: GitHub Copilot extractor/applier uses relative CWD paths for MCP config and instructions

[FZ2000]

Summary

The GitHub Copilot extractor and applier use relative paths for .vscode/mcp.json and .github/copilot-instructions.md. This means the actual files read/written depend entirely on the current working directory when apc is run — making the tool unreliable when invoked from different directories.

Steps to Reproduce

# Step 1: Run mcp sync from one directory
cd ~/project-a
apc mcp sync --all -y

# Step 2: Run collect from another directory
cd ~/project-b
apc collect -y
# github-copilot shows 0 MCP servers — because it reads .vscode/mcp.json from project-b, not project-a!

# Step 3: Verify the config was written to CWD, not a global location
ls ~/project-a/.vscode/mcp.json   # exists
ls ~/project-b/.vscode/mcp.json   # does not exist

Actual Behavior

• CopilotApplier.apply_mcp_servers() writes to .vscode/mcp.json (relative)
• CopilotExtractor.extract_mcp_servers() reads from .vscode/mcp.json (relative)
• CopilotApplier.apply_skills() writes to .github/copilot-instructions.md (relative)
• CopilotExtractor.extract_skills() reads from .github/copilot-instructions.md (relative)
• Config file ends up in whichever directory apc was invoked from

Expected Behavior

GitHub Copilot has a global MCP config location: ~/.vscode/mcp.json (VS Code user-level settings). apc should use this absolute path for global MCP management, not a relative .vscode/mcp.json.

Similarly, .github/copilot-instructions.md is project-scoped — for a global tool like apc, there should either be a documented fallback path or a warning that Copilot instructions are project-scoped.

Affected Code

# src/extractors/copilot.py and src/appliers/copilot.py
COPILOT_INSTRUCTIONS = Path(".github") / "copilot-instructions.md"  # relative!
VSCODE_MCP_JSON = Path(".vscode") / "mcp.json"                       # relative!

Proposed Fix

VSCODE_MCP_JSON = Path.home() / ".vscode" / "mcp.json"  # global user config
# Or: Path(os.environ.get('VSCODE_APPDATA', Path.home() / '.vscode')) / 'mcp.json'

Environment

• macOS Darwin 25.2.0 (arm64)
• apc version 0.1.0
• Verified by running apc mcp sync --all from ~/.openclaw/workspace and finding .vscode/mcp.json written there

Severity

High — The feature is silently broken for any user who doesn't always run apc from the same project directory.

[FZ2000]

Fixed in commit 368ddb5 on branch fix/bug-patrol-33-42-47-31-34. See the branch for full diff.