Reconstruct per-session and per-turn span trees (AGENT/LLM/TOOL, with
subagents nested under their delegate_task span) straight from SQLite — no
new write path. Turn-scoping splits on real user prompts and folds
synthetic continuations ([ASYNC DELEGATION ...], [IMPORTANT: ...]) into the
turn that spawned them. Exports to OTLP/JSON and Chrome Trace formats.
