test(slm-agent): tests are invisible to CI (not in pytest testpaths) and version_test.py fails standalone (ModuleNotFoundError 'slm')

Problem

Two related gaps found 2026-07-15 while adding health_collector_probe_test.py (#11723):

autobot-slm-agent is NOT in repo-root pytest.ini testpaths — none of its colocated tests run in CI (Unit & Integration Tests never collects them).
autobot-slm-agent/version_test.py fails all 14 tests when run manually (ModuleNotFoundError: No module named 'slm') — broken imports that CI never catches because of (1).

Same standalone-fragility family as #11248 (slm-backend conftest stubs) but different mechanism.

PR #11750 (merged to Dev_new_gui) references this issue with a close keyword.

test(slm-agent): add to CI testpaths + repair version_test imports (#11748)

If this issue is fully resolved, close it manually. If work remains, no action is needed.

Closed — merged to Dev_new_gui via PR #11750, squash commit 7a95b99d7.

AC evidence (verbatim):

"autobot-slm-agent added to testpaths (or an explicit CI step runs its tests)" — ✅ pytest.ini testpaths now includes autobot-slm-agent.
"version_test.py imports fixed so the suite passes" — ✅ imports repaired (flat-dir sibling resolution, same pattern as health_collector_probe_test.py); no version.py behavior bugs found — all 14 assertions correct once imports resolved.
"All colocated slm-agent tests green in CI" — ✅ pytest autobot-slm-agent -q from repo root → 21 passed (re-run by main session); other collection roots unaffected (tests/services still collects 314).

Related pre-existing legacy-tree failure noted on #11248 (autobot-slm-backend/slm health_collector_state_change_test.py).