fix(ui): a double-click on Trigger Auto Integrate sent two mutations

[logicflakes]

The problem

autoIntegrateFeatureSet is not idempotent. Server-side it gathers each dependency's latest release, asks whether a matching product release already exists, and creates one if not — a check-then-act that takes no lock, so two in-flight calls can both find nothing and both create a product release.

The control is a plain n-icon with an @click handler: no built-in disabled or loading state, and the handler had no re-entry guard. A double-click fired two concurrent mutations.

The fix

Guards on an in-flight ref and reflects it in the control — reduced opacity, not-allowed cursor, and the tooltip switching to "Auto Integrate in progress...".

Reset in a finally, not after the notify, so a failed mutation cannot leave the button permanently dead.

Why this instead of a server-side lock

The server-side fix was implemented and measured (relizaio/rearm-saas#408, now closed): four concurrent calls did produce four product releases. But the evidence did not justify shipping it:

• Zero feature sets in sandbox data have two product releases sharing a parent set — the path being unguarded had never actually caused harm. The 4/4 number came from a synthetic four-thread harness, not a realistic scenario.
• The lock would have been held across createProductRelease -> createRelease, which performs synchronous external I/O (GitHub build trigger, email send). A stalled user request would then block the automatic integrator for that feature set until a 30s lock timeout — a failure mode that does not exist today.

Trading a real new failure mode for a theoretical one was the wrong direction. A double-click is the realistic trigger, and this covers it with no locking, no new coupling, and no risk to the version pipeline.

Checks

• UI build clean.
• No new lint violations — the repo's error count is unchanged from main at 273 (pre-existing, repo-wide). My first attempt added 13 by wrapping the body in try without re-indenting; fixed.

Co-Authored-By: Claude noreply@anthropic.com

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