SaveColumn and SaveMercenary now check RowsAffected() and return a
wrapped ErrCharacterNotFound when 0 rows are updated, preventing
silent data loss when a character ID is missing or mismatched.
AdjustInt already detects this via its RETURNING scan — no change.
Daily mission packet structs (Get/SetDailyMission*) now parse the
AckHandle instead of returning NOT IMPLEMENTED, letting handlers
send empty-list success ACKs and avoiding client softlocks.
Also adds tests for dashboard stats endpoint and for five guild
repo methods (SetAllianceRecruiting, RolloverDailyRP,
AddWeeklyBonusUsers, InsertKillLog, ClearTreasureHunt) that
had no coverage.
