submit` ready-state focus pass¶

Motivation¶

Two small UX papercuts on the New Search page surfaced during a walk-through:

Selecting an example sequence in the Load example modal fired a semantically empty toast (Example loaded — MPXV F3L - NC_003310.1). The textarea content already changes, the program tab flips to blastn, and the modal closes — the toast adds noise without information.
When the user fills in the last required field and validation finally passes, the Run BLAST button sits quietly at the bottom of the rail. There is no visual handoff telling the user "you're done; press this".

The "Example loaded — …" toast is gone. The modal close + new FASTA in the textarea is the only feedback now.
On the false → true transition of canSubmit, the Run BLAST button emits a one-shot accent-tinted pulse (two cycles, ~1.4 s total) so it catches the eye. The pulse is suppressed under prefers-reduced-motion.
The same transition also moves keyboard focus onto the Run BLAST button so Enter submits, but only when the user is not actively typing: if document.activeElement is an <input>, <textarea>, <select>, or a contentEditable element, the focus jump is skipped and only the pulse plays. This avoids stealing the caret mid-typing (e.g. while still entering the job title).
The hidden mobile-footer variant and the visible desktop rail variant carry the same logic; only the button whose layout is currently visible (offsetParent !== null) is focused.

None — pure frontend / styling change.

File	Change
`web/src/pages/blastSubmit/QuerySection.tsx`	Drop the `toast("Example loaded — …")` call from `loadExample`.
`web/src/pages/blastSubmit/SubmitSummaryRail.tsx`	Add `runBtnRef`, `wasReadyRef`, `readyPulse` state, and a transition-edge `useEffect` that focuses the Run BLAST button (when no text input is active) and toggles a one-shot CSS class.
`web/src/pages/blastSubmit/BlastSubmitFooter.tsx`	Mirror the same logic on the mobile footer variant.
`web/src/theme/glass.css`	Add `@keyframes blast-submit-ready-pulse` + `.blast-submit-btn--ready-pulse` modifier; respect `prefers-reduced-motion: reduce`.

cd web && npm run build — clean, 6.68 s, no TypeScript errors.
Manual: open /blast/submit, fill required fields. The Run BLAST button pulses on the transition into the ready state; focus jumps to it only when the previously-active element is not a text input. Loading an example via the modal no longer raises a toast.