Fix terminal color report routing

[Misaka (chuxubank)]

Summary

Route dynamic terminal color reports (OSC 10/11/12) back to the child PTY instead of treating them as shell keypresses.

Programs such as chezmoi query the terminal background with OSC 11;?. Inside an inshellisense session, the query reaches the host terminal, but its OSC 11;rgb:... response currently enters readline as user input and is printed at the prompt.

Changes

• track pending OSC 10/11/12 queries in ISTerm, alongside the existing cursor-position query tracking
• parse BEL- and ST-terminated color reports from host terminal input
• forward reports only when the child issued the matching selector query
• keep incomplete reports across input chunks and preserve unrelated input
• add unit coverage for both terminators, chunking, trailing input, and unrelated OSC sequences

Validation

• npm run lint
• npm test -- --runInBand — 207 passed, 10 skipped
• npm run build
• targeted test and TypeScript build under the CI Node version (22.21.1)

npm run test:e2e -- --runInBand did not complete in the local nested inshellisense environment and was stopped after 30 minutes; the cross-platform GitHub Actions matrix should provide the authoritative E2E result.

[Misaka (chuxubank)]

@microsoft-github-policy-service agree