The seam extraction had landed partially, but src/cli/main.js still imported helper modules while keeping local parser and dispatch copies. That left the runtime brittle and previously caused src/cli/main.js to fail syntax loading once the imported names overlapped with local declarations.

This commit makes main.js rely on src/cli/args.js, src/cli/dispatch.js, and src/git/index.js as the authoritative seams, and it folds the setup --current alias into the shared repo-traversal parser so setup and doctor stay aligned on the same single-repo behavior.

Constraint: Preserve the existing gx command surface and nested-repo traversal semantics
Rejected: Split setup --current into a separate branch | the parser extraction already owned the same seam and proof surface
Confidence: high
Scope-risk: moderate
Reversibility: clean
Directive: Keep src/cli/main.js as a dispatcher and integration point; do not reintroduce local parser or dispatch helper copies without moving ownership back deliberately
Tested: node --check src/cli/main.js
Tested: node --check src/cli/args.js
Tested: node --check src/cli/dispatch.js
Tested: node --check src/git/index.js
Tested: node --test test/cli-args-dispatch.test.js
Tested: node --test test/metadata.test.js
Tested: node --test test/setup.test.js
Tested: node --test test/doctor.test.js
Tested: npm test
Tested: openspec validate agent-codex-split-cli-main-args-dispatch-2026-04-22-13-48 --type change --strict
Tested: openspec validate setup-current-single-repo-alias --type change --strict
Tested: openspec validate --specs (no items found)
Not-tested: branch finish/PR merge/cleanup flow