skills: hide orchestrator skills with a local executor

[jif-oai]

Why

App-server threads without a local executor need orchestrator-owned skills from the hosted codex_apps MCP server. Threads with the local executor already discover installed skills from the local filesystem.

After the orchestrator skill provider was enabled for every app-server thread, local-executor threads also received the hosted skill catalog and the skills.list and skills.read tools. This changed the existing local behavior and could expose a second hosted copy of a skill that was already installed locally.

What changed

• Expose the thread's selected execution environments to extensions at thread startup.
• Enable orchestrator skills only when the reserved local environment is not selected.
• Apply that decision consistently to hosted skill catalog discovery, explicit skill injection, and the skills.list and skills.read tools.

Verification

• The existing no-executor app-server test continues to verify hosted skill discovery, invocation, and child-resource reads.
• A new app-server test verifies that local-executor threads do not receive hosted skill context or skills.* tools.

[chatgpt-codex-connector]

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