[FEATURE] Improve VS Code runtime detection: use `.vscode/` directory presence as fallback

[sergio-sisternes-epam]

Is your feature request related to a problem? Please describe.

The current VS Code runtime detection relies exclusively on shutil.which("code") — i.e., whether the code CLI command is on the system PATH. On macOS, many users have VS Code installed but have never run "Shell Command: Install 'code' command in PATH" from the command palette. This means APM silently skips VS Code configuration even when the user is clearly working inside VS Code (evidenced by a .vscode/ directory in the project).

This leads to inconsistent behavior across machines with the same OS and the same APM build:

• Machine A (has code on PATH): configures for Copilot, Codex, and VS Code.
• Machine B (no code on PATH, but has .vscode/ in the project): configures for Copilot only, missing VS Code entirely.

The relevant detection logic is in src/apm_cli/integration/mcp_integrator.py (lines ~833–853):

if runtime_name == "vscode":
    if shutil.which("code") is not None:
        ClientFactory.create_client(runtime_name)
        installed_runtimes.append(runtime_name)

Describe the solution you'd like

APM should use a .vscode/ directory presence check as a fallback when shutil.which("code") returns None, similar to how Cursor and OpenCode detection already work:

if runtime_name == "vscode":
    if shutil.which("code") is not None or (Path.cwd() / ".vscode").is_dir():
        ClientFactory.create_client(runtime_name)
        installed_runtimes.append(runtime_name)

This makes the detection consistent with the existing pattern for Cursor (.cursor/) and OpenCode (.opencode/), and correctly recognizes that the user is working in a VS Code context.

Describe alternatives you've considered

1. Check for VS Code application bundle on macOS — e.g., look for /Applications/Visual Studio Code.app. This is more fragile (non-standard install paths, Insiders edition, etc.) and platform-specific.
2. Check for $VSCODE_* environment variables — VS Code sets variables like VSCODE_PID when running in its integrated terminal. However, this doesn't help when APM is run from a standalone terminal.
3. Do nothing and document it — Require users to install the code CLI command. This hurts developer experience since the current behavior is confusing and silent.

Additional context

• The Cursor and OpenCode runtimes already use directory-presence detection (.cursor/, .opencode/), so extending this pattern to VS Code (.vscode/) is consistent with the existing architecture.
• On a fresh macOS install, VS Code does not add code to PATH by default — the user must explicitly do so. This is a common source of confusion.
• The apm install output gives no indication that VS Code was skipped due to PATH issues, making it hard for users to diagnose.