Add 'Connect to Actions Job Debugger' command

[rentziass]

This is the first step toward bringing the Actions job debugging experience into VS Code.

This PR adds the extension-side connect flow:

• A new command ('GitHub Actions: Connect to Actions Job Debugger...') that prompts for a Dev Tunnel wss:// URL and starts a debug session.
• A WebSocket-based inline debug adapter (DebugAdapterInlineImplementation) that speaks DAP-over-WebSocket directly to the runner — no local TCP bridge needed.
• Authentication using the existing VS Code GitHub session token, sent as a Bearer token on the WebSocket handshake.

The tunnel URL is entered manually for now. Once the server-side
endpoint that serves the debugger URL for a job is deployed, we can
automate this (and eventually add 're-run with debugger' directly from
the extension).

Workarounds for VS Code quirks (to be removed as the runner evolves):

• Synthetic source references on stack frames so VS Code auto-focuses the top frame and loads variables on connect/step.
• Buffering of early 'stopped' events that the runner sends before VS Code completes the DAP handshake.

[Copilot]

Pull request overview

Adds an initial VS Code-side “connect” flow for the GitHub Actions Job Debugger MVP, enabling a DAP-over-WebSocket debug session to an Actions runner via a Dev Tunnel URL and GitHub authentication.

Changes:

• Adds a new command to prompt for a Dev Tunnel wss:// URL and start an attach debug session.
• Implements an inline debug adapter that bridges DAP messages over WebSocket (with keepalive and early-event buffering).
• Adds tunnel URL validation + unit tests, and wires up debugger contributions/dependencies.

Show a summary per file

File	Description
src/extension.ts	Registers the new debugger feature during extension activation.
src/debugger/debugger.ts	Implements the command + debug adapter factory/tracker and token handoff.
src/debugger/webSocketDapAdapter.ts	Adds a DAP-over-WebSocket inline adapter with keepalive and message patching/buffering.
src/debugger/tunnelUrl.ts	Validates tunnel URLs to restrict token exposure to approved domains/scheme.
src/debugger/tunnelUrl.test.ts	Adds unit tests for tunnel URL validation.
README.md	Documents the preview connect flow for the debugger.
package.json	Contributes the debugger type/command and adds ws dependencies/activation hook.
package-lock.json	Locks ws and @types/ws additions.

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package.json:32

• The new command is contributed in package.json but the extension isn’t activated on command execution. Without an onCommand:github-actions.debugger.connect activation event, users in workspaces that don’t match the existing activation events (e.g. empty workspace) may see the command but it won’t run because it isn’t registered yet. Add an onCommand activation event for this command (and keep onDebugResolve for sessions started other ways).

  "activationEvents": [
    "onView:workflows",
    "onView:settings",
    "onDebugResolve:github-actions-job",
    "workspaceContains:**/.github/workflows/**",
    "workspaceContains:**/action.yml",
    "workspaceContains:**/action.yaml"
  ],

• Files reviewed: 7/8 changed files
• Comments generated: 6