The version guard that was always true

We wrote @available(macOS 26.0, *) around dictation's Swift code, guarding a feature that only exists on macOS 26. Correct code, real guard, and the app would still have died at launch on every older Mac.

The reason is almost funny. Our build compiled that file targeting macOS 26 itself, the exact version being guarded against. Set your compiler's floor to the thing you're checking for, and the check turns true before your code ever runs a single if: 40 Speech symbols went in as ordinary strong binds instead of weak ones, resolved by the OS loader before main starts.

A runtime check is only as honest as the layers underneath it agree to be. Ours was true in the source, true in review, and quietly cancelled by a build flag nobody was reading as a decision.

Fixed now: the Swift target reads the app's real floor, Speech links weak, and the minimum OS version lives in exactly one place instead of the three that used to disagree with each other.