b86f067bfb
opencode-builder.sh: major reliability and correctness fixes: - Parallel pre-fetch per pool: ALL list_prs_*.ts scripts for a pool now launch in parallel (background jobs), results cached to temp files. Each pool iteration fetches all work-group data in ONE parallel batch (~90s) instead of 11 sequential ~90s calls (~990s). The bottleneck is Forgejo API speed, not sequential script execution. - Timeouts everywhere: SCRIPT_TIMEOUT_SEC raised 60s→300s (Forgejo is slow). find_sessions_by_prefix and other session_* scripts get 30s timeout via the timeout(1) utility. fetch_list_script catches timeout exit codes (124, 137, 139, 143) and returns [] gracefully. - Prompt builders fixed: build_impl_prompt, build_merge_prompt, build_review_prompt now collapse newlines in title/body via tr+sed so the prompt file stays valid as plain text. Full item JSON embedded as compact single-line (jq -c .) at end of prompt. - Verbose step logging: [step2], [pool:NAME] prefixes throughout main loop show exactly which stage is running and where any hang occurs. - BUILDER_DEBUG=1 env var enables bash -x tracing for deep debugging. Note: find_sessions_by_prefix --status busy returns empty (OpenCode /session/status only reports the supervisor session). busy_count=0 when all session status fields are empty, making all slots available. The total session count is logged alongside active count for visibility.