Summary

• remove the legacy core logger and Effect logger wrapper
• route Effect logs to one shared append-only opencode.log with readable logfmt output and a per-run run_id
• preserve --print-logs via an explicit stderr sink and --log-level via Effect minimum log levels
• migrate Effect-context logs to native Effect.log* calls and remove imperative logging outside Effect contexts

Testing

• bun typecheck in packages/core
• bun typecheck in packages/opencode
• bun typecheck in packages/server
• bun typecheck in packages/desktop
• bun test test/effect/observability.test.ts in packages/core
• bun test test/effect/app-runtime-logger.test.ts in packages/opencode
• git diff --check origin/dev...HEAD

Notes

• the shared log file intentionally appends across concurrent runs; every line includes run_id
• LSP stderr pipes continue to be drained without logging to avoid child-process deadlocks