Prepare OpenGhost public repo hygiene

[VAIBHAVSING]

Summary

• remove committed Python cache output and ignore future Python bytecode
• add security, contribution, conduct, issue, and PR templates for public GitHub readiness
• move the maintainer sandbox image context from developer/docker to docker and update references
• correct the sandbox image OCI license label to Apache-2.0
• configure main branch protection separately via GitHub API

Validation

• python3 /home/vsing/.codex/skills/.system/skill-creator/scripts/quick_validate.py skills/openghost-skill
• bash -n openghost && bash -n skills/openghost && bash -n skills/openghost-skill/openghost && bash -n skills/openghost-skill/scripts/openghost.sh && bash -n skills/openghost-skill/scripts/verify-toolchain.sh && bash -n docker/healthcheck.sh
• PYTHONPYCACHEPREFIX=/tmp/openghost-pycache-fix python3 -m py_compile skills/openghost-skill/scripts/select-modules.py skills/openghost-skill/scripts/openghost-state.py
• git diff --check
• YAML parse check for GitHub workflow and issue template config

Docker runtime validation was not run because the local Docker daemon is not reachable.