fix: honor explicit pause requests while smart stepping

[debugmcpdev]

An explicit DAP pause in skipped or unmapped code can be acknowledged and then consumed by automatic stepping, leaving the debuggee running without a usable stopped event.

Honor the explicit pause intent already recorded by Thread.pause() and reset the automatic-step counter. A manual pause can now expose an internal or generated frame; ordinary stepping, pauses without explicit pause intent, and the existing breakpoint/exception/entry exemptions retain their behavior. No launch defaults or public configuration change.

Fixes #2412

Validation

Tested on Windows x64 with Node v24.14.1, based on 41bd9bb831a46c2668cab14d8455e8e3bff58477.

• New unit coverage exercises skipped and unmapped frames, preserved step directions and deliberate stops, and counter reset. Before the fix, four assertions fail; all 18 cases pass afterward.
• The new Node integration test times out on unpatched main after an acknowledged pause and 1,437 continued events without a stopped event. With the fix, it pauses, reads the stack, evaluates an expression, and resumes.
• npm run compile, npm run test:types, npm run test:unit (284 passing), and npm run test:lint pass.
• npm run test:golden: 435 passing, 8 pending, 2 failing. The Deno doesn't duplicate --allow-all failure also reproduces on unpatched main. pretty print sources / bps passes when rerun on both main and this branch; a focused rerun with the new pause regression has 2 passing tests.
• The rebuilt standalone DAP server passes the Express reproduction with smartStep: true. Downstream dogfooding through mcp-debugger's development proxy also succeeds: pause an idle mcp-debugger server, inspect/evaluate its state, hit a source-mapped TypeScript breakpoint in its HTTP handler, step over, and resume an HTTP 200 response.

[debugmcpdev]

@microsoft-github-policy-service agree

[Connor Peet (connor4312)]

thanks!