[codex] Rewrite tc CLI in Go

[techulus-agent]

Summary

• Rewrites the unreleased tc CLI from TypeScript/Bun to Go with Cobra-based commands.
• Preserves the existing auth, manifest, apply/deploy/status/logs workflows and config path compatibility.
• Aligns local manifest validation with the web schema and adds focused Go tests.
• Adds CLI CI and publishes tc-* binaries/checksums through the release workflow.

Impact

Users get a single static tc binary with first-class help, completions, version output, and the same backend API contracts as before. The old Bun build/dependency files are removed because the CLI was never released.

Validation

• /opt/homebrew/bin/go test ./...
• /opt/homebrew/bin/go vet ./...
• /private/tmp/staticcheck ./...
• tc version, tc --help, tc completion zsh, tc init
• Cross-platform build smoke for darwin/linux/windows targets
• git diff --check

[github-actions]

React Doctor found no new issues. 🎉

_{Reviewed by React Doctor for commit 8e320fa.}