Release v0.3.1 · Z-M-Huang/cc-proficiency

Session date validation & merge fixes

Validate session timestamps before use — buildRecentSessionsForRemote now checks that timestamps are parseable dates. Sessions with no valid timestamp are dropped instead of silently using new Date(), which could produce incorrect dates.
Refresh dates on remote merge — when a session already exists in the remote store, its date field is now updated if the local timestamp yields a different (corrected) value.
Extracted buildRecentSessionsForRemote — factored out of mergeAndPush for clarity and testability.

Added tests for buildRecentSessionsForRemote (valid, invalid, and missing timestamps).
Added tests for date-refresh behavior in mergeIntoRemote.

Full Changelog: v0.3.0...v0.3.1