Distill v2.0.28

Fixes

• Worker model is now per instance: several Distill windows no longer overwrite each other's worker, /worker-model always applies to the current window, and new/resumed sessions keep that window's worker.
• The <orchestration> prompt section follows the session's real worker and main model, including after switches and on resumed sessions.

Cheaper parallel delegation

• Batch delegation rules in the main prompt; explore searches before reading whole files.
• Subagent reports capped (full text stored on disk); repository_review limited to the child's own files and shown in the TUI.
• Visible warning when a child falls back to the main model; model= in <subagent_meta>.
• Background children finishing together wake the main model once; long children get one "report now" reminder.
• Sibling subagents share prompt cache; file edits lock per path across sessions.
• Jev B6 delegation decision recorded in shadow mode (hint behind b6_delegation_hint).
• Late background-child usage counted in the turn that spawned it; new cohort-parallel-v1 cost benchmark.