## Why
Skill metadata accepted a `permissions` block and stored the result on
`SkillMetadata`, but that data was never consumed by runtime behavior.
Leaving the dead parsing path in place makes it look like skills can
widen or otherwise influence execution permissions when, in practice,
declared skill permissions are ignored.
This change removes that misleading surface area so the skill metadata
model matches what the system actually uses.
## What changed
- removed `permission_profile` and `managed_network_override` from
`core-skills::SkillMetadata`
- stopped parsing `permissions` from skill metadata in
`core-skills/src/loader.rs`
- deleted the loader tests that only exercised the removed permissions
parsing path
- cleaned up dependent `SkillMetadata` constructors in tests and TUI
code that were only carrying `None` for those fields
## Testing
- `cargo test -p codex-core-skills`
- `cargo test -p codex-tui
submission_prefers_selected_duplicate_skill_path`
- `just argument-comment-lint`
## Summary
- move skill loading and management into codex-core-skills
- leave codex-core with the thin integration layer and shared wiring
## Testing
- CI
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Co-authored-by: Codex <noreply@openai.com>
