Summary

• make TUI/gateway session.resume follow compression continuations through db.get_compression_tip(...)
• add regression coverage that resumes a compression root and verifies the live continuation tip is reopened and hydrated

Why

A resumed compressed conversation could appear to lose post-compaction messages because session.resume reopened the old root session instead of the latest continuation tip. The data was still present in session lineage, but this path was not following it.

Validation

• ./scripts/run_tests.sh -n 0 tests/tui_gateway/test_protocol.py tests/test_hermes_state.py -q --tb=short, 266 passed
• python -m compileall -q tui_gateway/server.py tests/tui_gateway/test_protocol.py
• git diff --check origin/main...HEAD

Notes

• Rebuilt on current main after fix(ci): unblock shared PR checks #21012 so the old shared baseline commit is no longer part of this PR