feat: Go-first opentmux runtime with TS compatibility shims

[AnganSamadder]

Summary

This PR introduces a Go-first runtime architecture for opentmux while preserving plugin/CLI compatibility through thin TypeScript shims and legacy fallbacks.

The objective is to move high-throughput and process-heavy behavior out of Node/TS and into Go, while keeping user-facing behavior stable and preserving the existing package entrypoints.

What Changed

1. Go platform foundation

• Added Go module and dependency management:
  • go.mod, go.sum
• Added Buf v2 config and lockfile:
  • buf.yaml, buf.gen.yaml, buf.lock
• Added control-plane protobuf contract:
  • proto/opentmux/v1/opentmux.proto
• Added generated artifacts:
  • gen/go/...
  • gen/ts/...

2. Go runtime binaries

• Added Go CLI wrapper:
  • cmd/opentmux/main.go
• Added Go daemon:
  • cmd/opentmuxd/main.go
• Added Go control client:
  • cmd/opentmuxctl/main.go

3. Core Go runtime packages

• Config loading + normalization:
  • internal/config/config.go
• Structured logging:
  • internal/logging/logger.go
• Metrics snapshot support:
  • internal/metrics/metrics.go
• Process helpers (PID lookup/kill/wait/etc):
  • internal/process/process.go
• tmux operations:
  • internal/tmux/tmux.go
• Spawn queue implementation:
  • internal/spawnqueue/queue.go
• Zombie reaper:
  • internal/reaper/reaper.go
• Session manager lifecycle and polling:
  • internal/sessionmanager/manager.go
• RPC control service:
  • internal/control/service.go

4. TypeScript compatibility shim

• Replaced plugin entrypoint with Go-control shim:
  • src/index.ts
• Replaced bin entrypoint with Go-CLI shim:
  • src/bin/opentmux.ts
• Added runtime binary resolver/executor:
  • src/utils/go-runtime.ts
• Preserved legacy behavior as fallback:
  • src/legacy-plugin.ts
  • src/bin/opentmux-legacy.ts

5. Build/CI and benchmarking

• Bun-driven Go runtime build script:
  • scripts/build-go-runtime.ts
• Burst benchmark harness:
  • scripts/bench/run-burst.ts
  • internal/spawnqueue/queue_bench_test.go
• Updated npm scripts:
  • build, build:go, proto:generate, bench:burst
• Updated publish workflow to install Go and build release binaries:
  • .github/workflows/publish.yml

6. Documentation updates

• Rewrite/development notes added to:
  • README.md
  • docs/LOCAL_DEVELOPMENT.md

Behavior/Parity Notes

• TS compatibility is preserved via shim + fallback.
• Go queue parity was improved to match TS duplicate coalescing behavior for both queued and in-flight items.

Tests and Validation

Automated checks run

• go test ./...
• go test -race ./internal/spawnqueue ./internal/control ./internal/config
• go vet ./...
• bun run proto:generate
• bun run typecheck
• bun test
• bun run build
• bun run scripts/bench/run-burst.ts

Manual smoke checks run

• Daemon lifecycle:
  • start opentmuxd
  • opentmuxctl init
  • opentmuxctl stats
  • opentmuxctl shutdown
  • verified clean daemon exit

Known Constraints

• edition = "2024" was not fully compatible with the current stable generation path used here; proto currently uses syntax = "proto3" for reliable generation.
• Existing repo scripts test-plugin.sh and test-multiport.sh are environment/path-sensitive:
  • test-plugin.sh requires an active tmux session
  • test-multiport.sh references a legacy path outside this repo

Impact

This PR establishes a production-ready migration scaffold: Go-first runtime, compatibility shims, build pipeline integration, and parity-focused tests, without removing legacy fallback paths yet.