c3671d86cf
Implements Khala cloud workflow orchestrator (Phase 0-4): - Project scaffolding: Hono + Wrangler + D1 + DO - D1 schema: agents, threads, messages, tasks tables - Data access layer with atomic claim/release - Agent auth (SHA-256 Bearer token) + admin API - ThreadDO workflow engine with JSONata moderator - Task queue API: poll/claim/release - Cron-based timeout sweep - Ping-pong demo workflow Closes #124, closes #125, closes #127, closes #128, closes #129