Plans with 1-2 tasks now execute inline (Pattern C) instead of spawning
a subagent (Pattern A). This avoids ~14K token subagent spawn overhead
and preserves the orchestrator's prompt cache for small plans.
The threshold is configurable via workflow.inline_plan_threshold
(default: 2). Set to 0 to always spawn subagents. Plans above the
threshold continue to use checkpoint-based routing as before.
Closes#1979
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>