2a86049f0f
ImmutablePrefix caches system prompt + tool specs after first build() so subsequent turns reuse identical byte sequences. AppendOnlyLog converts messages once via syncMessages() and only appends deltas on further turns — prior-turn bytes stay stable. - New module: packages/agent/src/append-only-context.ts StablePrefix, AppendOnlyLog, AppendOnlyContextManager - AppendOnlyContextManager added to AgentLoopConfig - Wired into streamAssistantResponse in agent-loop.ts - Toggleable via provider.appendOnlyContext setting (auto/on/off) - Default auto enables for deepseek provider - 38 tests covering prefix, log, sync, compaction handling - /session info surfaces current active state