feat(compression): flip in_place default to True + guard fix (#38763) [salvage #51959]

[teknium1]

Summary

Flips compression.in_place default False → True so compaction keeps one durable session id instead of rotating — eliminating the session-id rotation that was the root cause of a P1 cluster (#14238 lost pending response, #13840 search black-hole, #36777/#42228 TUI/desktop stale-cwd/sid). Bundles the guard fix that makes the flip safe.

Salvage of #51959 — cherry-picked onto current main, contributor authorship preserved (@srojk34's guard fix + @kshitijk4poor's flip/tests).

This is the staged flip after #49739 (in-place soft-archive machinery, [1/2]) merged and soaked. Rotation remains a working opt-out fallback via compression.in_place: false.

Why the guard fix MUST land with the flip

/compress and the gateway hygiene-compress both build a throwaway AIAgent without a session_db, so archive_and_compact can't run and _last_compaction_in_place stays False. Both guard sites read compression_in_place (the config flag — "is in-place enabled?") instead of _last_compaction_in_place (the result flag — "did in-place succeed?"). Harmless while the default is False; flip the default and every gateway compress passes the guard with no successful compaction → rewrite_transcript() replaces the transcript with summary-only (permanent data loss, the #21301 class). The fix points both guards at the result flag (matching the canonical read already at gateway/run.py).

Changes

• gateway/run.py, gateway/slash_commands.py: hygiene guard + /compress read _last_compaction_in_place (result flag) not compression_in_place (config flag).
• hermes_cli/config.py: compression.in_place default False → True.
• tests/gateway/test_session_hygiene.py: regression test — in-place configured but no session_db must preserve the transcript (fails without the guard fix).
• 7 rotation-asserting test sites pinned to in_place=False so the rotation fallback keeps coverage; test_in_place_compaction default assertion flipped to defaults_on.
• scripts/release.py: AUTHOR_MAP entry for @srojk34's legacy prefix-less noreply.

Validation

	Buggy (config flag)	Fixed (result flag)
in-place configured, no session_db, gateway compress	rewrite_transcript called with summary-only → data loss	transcript preserved

• Regression test fails with the guard reverted to the config-flag read, passes with the fix (verified locally).
• 44/44 targeted compression tests green (session_hygiene, in_place_compaction, rotation_state, logging_session_context, boundary_hook).
• Rebased onto current main; diff is the 11 intended files only (134/-9).

Closes #51959. Supersedes #50098.

Infographic

[github-actions]

🔎 Lint report: hermes/hermes-4efd4d14 vs origin/main

ruff

Total: 0 on HEAD, 0 on base (➖ 0)

🆕 New issues: none

✅ Fixed issues: none

Unchanged: 0 pre-existing issues carried over.

ty (type checker)

Total: 11275 on HEAD, 11265 on base (🆕 +10)

🆕 New issues (7):

Rule	Count
unresolved-attribute	7

First entries

tests/agent/test_compression_concurrent_fork.py:83: [unresolved-attribute] unresolved-attribute: Unresolved attribute `compression_in_place` on type `AIAgent`
tests/agent/test_compression_rotation_state.py:59: [unresolved-attribute] unresolved-attribute: Unresolved attribute `compression_in_place` on type `AIAgent`
tests/gateway/test_compression_concurrent_sessions.py:77: [unresolved-attribute] unresolved-attribute: Unresolved attribute `compression_in_place` on type `AIAgent`
tests/run_agent/test_compression_boundary_hook.py:185: [unresolved-attribute] unresolved-attribute: Unresolved attribute `compression_in_place` on type `AIAgent`
tests/agent/test_compression_logging_session_context.py:56: [unresolved-attribute] unresolved-attribute: Unresolved attribute `compression_in_place` on type `AIAgent`
run_agent.py:2989: [unresolved-attribute] unresolved-attribute: Object of type `Self@get_credits_spent_micros` has no attribute `_credits_session_start_micros`
tests/run_agent/test_credits_notices_toggle.py:76: [unresolved-attribute] unresolved-attribute: Unresolved attribute `_credits_session_start_micros` on type `AIAgent`

✅ Fixed issues (1):

Rule	Count
invalid-assignment	1

First entries

tests/run_agent/test_credits_notices_toggle.py:76: [invalid-assignment] invalid-assignment: Object of type `None` is not assignable to attribute `_credits_session_start_micros` of type `int`

Unchanged: 5940 pre-existing issues carried over.

Diagnostics are surfaced as warnings — this check never fails the build.