v0.9.0

Self-warming worker pool

Workers now spawn a replacement (with --timeout 60s) before executing their task, maintaining the pool automatically. This replaces the upfront pool spawning ceremony — sessions no longer need to pre-spawn workers at startup.

• One new per one used — each consumed worker spawns exactly one replacement, keeping the pool warm without waste
• Always prefer cworkers when an idle worker is available — zero startup overhead vs Agent tool fallback
• Burst parallelism (skills like /cv fanning out many agents): use regular Agent spawning — startup latency is negligible relative to work volume
• Team agents excluded — teams manage their own lifecycle, no pool participation
• Simplified session setup to just shadow registration
• Removed haiku from model selection (opus + sonnet only)
• Updated operational guide (--help-agent)