#7236 chore(skills): name directExecution as retired in the add-integration checklist

Follow-up to the directExecution retirement, from a review finding on the v0.8.16 release PR (#7224).

The add-integration transport checklist listed the property inside a bare enumeration:

No tool points to /api/..., constructs a URL back to Sim, declares request.internal, or directExecution, or has an HTTP fallback for an in-process operation

That stacks two disjunctions and drops the "retired" framing every other statement of the same rule carries — including line 71 of this very file, and the add-tools, add-trigger, and add-block skills. A reader scanning the checklist could reasonably take directExecution for a property that still exists and is merely discouraged, which is the opposite of the intent.

Now reads:

No tool points to /api/..., constructs a URL back to Sim, declares request.internal or the retired directExecution property, or has an HTTP fallback for an in-process operation

Wording only. The rule itself is unchanged, and it is enforced mechanically by check:tool-request-boundary, which fails with directExecution is retired; use InternalToolConfig.operation and a registered server handler.

Checks

• bun run lint — clean
• bun run check:audits — 39/39 pass (includes check:skills and check:tool-request-boundary)
• check-block-registry.ts origin/staging — pass
• skills:sync + agent-stream-docs:generate — no artifact drift