Update openai-curated Superpowers plugin to upstream 6.0.3

Summary

Follow-up to #28846: the superpowers@openai-curated / Codex marketplace package still appears to be pinned to 5.1.3, while upstream Superpowers has moved on again and now publishes 6.0.3.

Current behavior

• The local Codex remote plugin catalog entry for superpowers reports release 5.1.3.
• The Codex marketplace copy at .codex-plugin/plugin.json still reports \"version\": \"5.1.3\".
• The current Codex App session loaded Superpowers skills from openai-curated-remote/superpowers/5.1.3.

Expected behavior

Please update the Codex curated marketplace package for Superpowers to upstream 6.0.3, or document the marketplace pinning / update-lag policy so users know why reinstalling or refreshing still resolves to 5.1.3.

Evidence

• Existing report: #28846 noted 5.1.3 vs upstream 6.0.2 and is still open.
• Upstream Codex plugin manifest now reports \"version\": \"6.0.3\": https://github.com/obra/superpowers/blob/main/.codex-plugin/plugin.json
• Upstream latest release is v6.0.3: https://github.com/obra/superpowers/releases/tag/v6.0.3

Local verification

$ jq -r '.. | objects | select(.name? == "superpowers" and .release?) | "name=\(.name) release=\(.release.version) status=\(.status) policy=\(.installation_policy)"' ~/.codex/cache/remote_plugin_catalog/*.json
name=superpowers release=5.1.3 status=AVAILABLE policy=AVAILABLE

$ jq -r '.version' ~/.codex/.tmp/plugins/plugins/superpowers/.codex-plugin/plugin.json
5.1.3

$ curl -fsSL https://raw.githubusercontent.com/obra/superpowers/main/.codex-plugin/plugin.json | jq -r '.version'
6.0.3

Why this matters

Superpowers 6.0.x includes Codex-specific updates, including Codex SessionStart hook support and updated harness documentation, so the curated marketplace package is missing current Codex-facing fixes.