Summary

Fixes #14082.

This lets /resume <title> recover sessions when the user copies the width-limited title shown by the recent-session list.

Root cause

/resume tells users they can resume by session ID or title, but the recent-session table truncates titles. The resolver only accepted exact title matches (plus lineage suffixes), so copying the displayed title prefix failed with Session not found.

Fix

• Preserve the existing exact-title and numbered-lineage behavior.
• If exact/lineage resolution fails, accept a unique title prefix.
• Keep ambiguous prefixes unresolved so Hermes does not jump to the wrong session.
• Guard blank title input so it cannot prefix-match arbitrary sessions.

Validation

• /Users/stephenyu/Documents/hermes-agent/.venv/bin/python -m pytest tests/test_hermes_state.py::TestTitleLineage::test_resolve_blank_title_returns_none tests/test_hermes_state.py::TestTitleLineage::test_resolve_unique_title_prefix_from_truncated_display tests/test_hermes_state.py::TestTitleLineage::test_resolve_ambiguous_title_prefix_returns_none tests/test_hermes_state.py::TestTitleLineage::test_resolve_exact_title tests/test_hermes_state.py::TestTitleLineage::test_resolve_returns_latest_numbered tests/test_hermes_state.py::TestTitleSqlWildcards::test_resolve_title_with_percent tests/test_hermes_state.py::TestTitleSqlWildcards::test_resolve_title_with_underscore -q --tb=short
• /Users/stephenyu/Documents/hermes-agent/.venv/bin/python -m pytest tests/test_hermes_state.py -q --tb=short
• git diff --check