[codex] Record v0.2 alpha closure decision

[Atomics-hub]

What changed

• Added docs/v0.2-alpha-closure.md as the stop/ship decision for the v0.2 alpha train.
• Linked the closure decision from public readiness and v0.2 alpha release notes.
• Captured the evidence gates, shipped alpha surfaces, accepted alpha limits, and recommended post-alpha themes.

Why

We are freezing feature expansion for this run and closing on a credible installable local/team sidecar alpha rather than continuing to expand scope into hosted production work.

Validation

• cargo run --locked -- release-status --json | jq '{ready_for_alpha_rc, shipped_pass: ([.shipped_surfaces[].status] | all(. == "pass")), gates_pass: ([.verification_gates[].status] | all(. == "pass")), accepted_limits: [.accepted_limits[] | {name,status}], final_blockers: [.final_release_blockers[] | {name,status}]}'
• cargo run --locked -- release-ticket --out dist/release-ticket-alpha-closure --force --json | jq '{ready, objectives: [.checks[] | select(.name | startswith("objective:"))]}'
• cargo fmt --check
• cargo clippy --all-targets --all-features -- -D warnings
• cargo run --locked -- release-audit