Follow-up to the salvaged #57634 commits:
- agent/manual_compression_feedback.py: new describe_compression_lock_skip()
— single source of truth for lock-skip wording. A descriptive holder
string means another compressor CONFIRMED holds the lock ('already in
progress (holder: ...)'); True/None means acquisition failed without a
confirmed holder (hermes_state.try_acquire_compression_lock catches
sqlite3.Error internally and returns False), so the message says
'could not acquire ... the lock check failed' instead of falsely
claiming a concurrent compression is running.
- cli.py, gateway/slash_commands.py, tui_gateway/server.py (all three
in-process consumers: session.compress RPC, command.dispatch compress
branch, slash.exec mirror) now route through the shared helper.
- tui_gateway/server.py command.dispatch compress branch: catch
CompressionLockHeld explicitly — it previously fell into the generic
'compress failed' error handler.
- Deferred-notify contract (#69324): lock-skip discards the pending
context-engine notification (committed=False) in _compress_session_history
and the CLI path before returning.
- tests: lock-skip wording pins per surface, VISIBLE_COMPRESSION_MESSAGES
noise-filter carve-outs for both wordings, MagicMock signal opt-outs for
sibling tests added on main after the original PR.
