Deliver App Builder Golden nested workspace E2E slice

[kattsushi]

Requested outcome

Deliver PR 07 of the App Builder Golden feature chain: a real isolated nested Nx E2E harness for the generated Todo workspace.

Scope

• Materialize the generated Todo topology under an OS-temporary directory.
• Use a local Effect package distribution, an isolated Verdaccio registry, isolated pnpm store/state, and NX_DAEMON=false.
• Prove nested frozen dependency installation, Nx graph, test, typecheck, build, durable Todo CRUD/events, regeneration zero diff, and cleanup after success, verification failure, and interruption.
• Prove no nested Todo project pollutes root Nx discovery.

Acceptance criteria

• Child processes have bounded timeouts, explicit environments, no shell execution, and are terminated during finalization.
• Temporary workspace, registry state, pnpm store, Nx state, and registry daemon are removed on every outcome.
• The slice remains under the 700 changed-line native objective and does not include PR 08 showcase work.

Chain context

• Tracker: feat(app-builder): track platform delivery #92
• Parent slice: feat(app-builder): add deterministic replay #124 (feat/app-builder-golden-replay)
• Child branch: feat/app-builder-golden-nested-e2e
• Follow-up: PR 08 showcase and closure

Rollback

Revert only packages/app-builder/e2e/**, the PR 07 task marks, and the E2E package lockfile entry. Earlier planning, generation, Todo behavior, protocol, and replay slices remain intact.

[kattsushi]

Closing as not planned because Effectify App Builder has been retired in favor of contributing to lloydrichards/stack-effect. No App Builder implementation is retained on dev.