CLI: scaffold publish requirements

[zkwentz]

What & Why

Strict publish validation needs declared resource and network requirements, but legacy scaffolds omitted them. This PR adds a Harbor schema 1.1 task.toml to new environments and gives echo_env a truthful canonical envelope.

Risk & Review Guidance

• Risk level: MEDIUM — changes generated project configuration and introduces a migration requirement
• Task class: migration
• Review focus: src/openenv/cli/templates/openenv_env/task.toml:1 for generated defaults; envs/echo_env/task.toml:1 for canonical values; generator checklist updates for truthful configuration
• Blast radius: Bad defaults can request the wrong hardware/network posture or encourage authors to copy inaccurate requirements.

Decisions & Alternatives

• Schema 1.1 is auxiliary input — keeps the core planner spec-neutral.
• Scaffold conservative explicit fields — authors must review CPU, memory, storage, GPU, and internet values.
• Do not bulk-invent configs for legacy environments — unknown requirements remain visible blockers.

Verification

• PASS: PYTHONPATH=src:envs .venv/bin/python -m pytest tests/ -q -m 'not integration' — 1,559 passed, 114 skipped, 31 external integration tests deselected on the complete stack.
• PASS: Fork whole-stack CI — 7/7 checks passed, including Python 3.11/3.12, lint, docs, lock validation, and package smoke tests.
• NOT verified: Resource values for legacy environments were intentionally not inferred.

Scope & Non-Goals

• This PR does not migrate every existing environment; owners need to declare truthful values.

Breaking Changes / Migration Notes

New openenv init output includes task.toml. Older environments must add a truthful requirements envelope before the strict publish gate can pass.

Stack

PR 15 of 17; depends on #955.

Full 17-PR stack

1. #942 RFC 008: Spec-neutral local and remote validation architecture
2. #943 Validation foundation: spec-neutral contracts and adapters
3. #944 Validation policy: spec-aware check registry and planner
4. #945 Validation executor: hardened shared reports and eligibility
5. #946 Local validation API: execution-model-aware profiles
6. #947 CLI: validation profiles and shared reports
7. #948 HF runtime: dedicated sandbox execution mode
8. #949 HF certification: enforce trusted dedicated isolation
9. #950 [RFC 008] Define remote author validation and publish gating
10. #951 Validation: unify CLI reports and add a strict publish profile
11. #952 Validation: add structured author diagnostics and remediation
12. #953 Validation: run author validation in dedicated HF Sandboxes
13. #954 Validation: isolate submitted code in author Sandboxes
14. #955 Validation: bind author reports to policy and source
15. #956 CLI: scaffold publish requirements ← current
16. #957 CLI: gate pushes on staged remote validation
17. #958 Docs: explain local, remote, and publish validation

All upstream PRs remain draft while RFC 008 is under review.