VS Code workspaces can expose a parent repo plus nested storefront/backend repos, and the Start agent command previously defaulted to the workspace root. That made it too easy to start the wrong lane when the user wanted a nested repo branch/worktree while keeping that nested repo's visible main checkout stable.

This adds bounded nested Git repo discovery to the Active Agents picker, keeps the installed template copy in sync, and adds a regression proving the terminal cwd follows the selected nested repo.

Constraint: VS Code Source Control commonly exposes nested repos in one workspace.

Rejected: Change branch-start semantics globally | the CLI already creates isolated worktrees when invoked from the correct repo root.

Confidence: high

Scope-risk: narrow

Directive: Keep the extension source and templates/vscode/guardex-active-agents/extension.js in sync for install parity.

Tested: node --test test/vscode-active-agents-session-state.test.js

Tested: node --check vscode/guardex-active-agents/extension.js

Tested: openspec validate agent-codex-codex-task-2026-05-11-15-20-2 --type change --strict

Tested: openspec validate --specs

Not-tested: Full npm test; metadata.test.js has unrelated release-lane failures for Cosign v4.1.2 vs expected v4.1.1 and missing README v7.0.43 notes.

Co-authored-by: OmX <omx@oh-my-codex.dev>