Conversation history source order

Synthetic local fixtures only; no private conversation, account or credentials. The desktop captures use 1512 × 982; the narrow capture uses 390 × 844.

• Before: opaque message-ID sorting puts the answer before its same-second question.
• After: the Session append order keeps the question before its answer.
• Narrow: the same source order remains readable at 390 px.

The existing conversation-history-recovery scenario also exercises failed older reads, draft retention, current-session send blocking, projection rehydration, retired observers and zero replay. The chat-route smoke checks complete long bodies, repeated text, scoped identity and deterministic cross-session ties. This qualifies source/display order and synthetic recovery, not complete pagination, reply threading, native input or real App/Lark media delivery.