fix: recover recorded reasoning effort from Codex thread settings

[capisoft-lib]

Summary

• Read reasoning_effort from Codex thread_settings_applied events when turn_context.effort is absent.
• Stop carrying a prior turn's effort into a turn without recorded effort.
• Invalidate the analysis cache and add regressions for both cases.

Verification

• npm run check with Node 24.19.0: 313 tests passed.
• git diff --check: passed.

Data limit

The screenshot's Conversation cba6dc20 has no effort in its two call records, turn context, applied settings, or local Codex thread state. This change leaves its effort unknown rather than inventing a value. It improves cases where the applied settings event does record the effort.