Validate v1.1 Dev Containers and Codespaces

[BrettKinny]

This was generated by AI during triage.

Type: HITL

What to build

Exercise the v1.1 Dev Container and GitHub Codespaces adapters through their real orchestration layers. Validate the tagged Candidate source build, postCreateCommand, noninteractive default selections, independent failure semantics, Workspace alignment, and rebuild persistence.

Record the source tag/SHA, resulting image ID, VS Code Dev Containers or Codespaces versions, host/runtime, configuration overrides, and pass/fail evidence in this issue. A Dev Container source rebuild is not expected to be byte-identical to the published Candidate digest.

Acceptance criteria

• VS Code Dev Containers builds the tagged Candidate source, opens /workspace as dev, and runs the real post-create command successfully.
• GitHub Codespaces runs the same post-create path with the documented default AI and SDK selections.
• Explicitly empty per-tier environment variables opt out; existing user Selections take precedence over defaults.
• If one setup section fails while another succeeds, the failed section returns nonzero and the successful section's Selection/observed tool remains intact.
• Rebuild/reopen preserves Workspace Selection state and Managed-home authentication/toolchains.
• Shell initialization is suppressed only during creation and works normally in the opened interactive terminal.
• Custom editor/TUI/SDK defaults reconcile on rebuild without repeating successful installs or erasing prior choices.
• Results and any failures are attached here and the v1.1 manual UAT checklist is updated.

Blocked by

None - can start immediately.