Improve Mirror interaction, scrolling, and pairing

[onevcat]

Summary

Continues #846 by @Awhisper and retains all 13 original commits, including source head 0a39b9ce3257456c500543f0e8a02dcfc911759c (last checked 2026-10-02 13:32:20 UTC).

• Separate interactive input from automation completion receipts.
• Add explicit remote scrolling, Mac styled scrollback, QR pairing, connection-detail paste, and device revocation.
• Fix Mac frame acknowledgements with fixed Ghostty titles and configuration reloads. Use a private OSC 7 parser marker and report a stalled parser after 30 seconds.
• Consume Android scroll completions once so reader recreation preserves subsequent reading positions.
• Add regression coverage and remove timing races from the full test suite.

Remote scrolling changes the Host's shared viewport, not an independent client history position. Styled-history limits and the plain-text fallback remain. Ghostty source and framework are unchanged.

Validation

• make test: 3,578 passed, 6 skipped, zero failures across four xcresult groups.
• make build-app and make check: passed, including 210 script tests, lint, formatting, and localization checks.
• CLI build, smoke, unit (304), and integration (106): passed.
• Android unit: 39 passed, 1 skipped; lint and all 9 remote-scroll emulator UI tests passed, including reader recreation.
• Static-title and reader-recreation regressions were observed before their fixes.

The app test build reports four dependency-scan warnings; the Debug app build has no warnings. iOS suites, physical-device pairing, and actual Android Activity rotation were not rerun. Android coverage recreates the reader composition while retaining its Session.

Merge requirement

Merge with a merge commit. Do not squash or rebase. This preserves @Awhisper's original commit identities. This replacement PR adds follow-up commits without rewriting the contribution.