perf(ui): Fluid shell performance follow-ups (post-#342 audit)

[ZhuchkaTriplesix]

Context

Static performance audit of Fluid / QueryaMotion on dev after #342 / #353 / #354 (2026-07-26).

Verdict: settle contract, motion levels, and virtual-grid rules look solid. Risk is composite / rebuild cost at 120 Hz (budget ≤ 8.3 ms).

Children

P0 — before 120 Hz green

• perf(ui): isolate tab strip spring rebuilds (Fluid F1) #357 F1 — isolate tab strip spring rebuilds
• perf(ui): RepaintBoundary + TickerMode for workspace morph layers (Fluid F2) #358 F2 — RepaintBoundary + TickerMode for workspace morph layers
• perf(ui): stop animating BackdropFilter blur sigma in dialogs (Fluid F3) #359 F3 — stop animating BackdropFilter blur sigma in dialogs

P1

• perf(ui): reduce split/sidebar layout thrash during drag settle (Fluid F4) #360 F4 — reduce split/sidebar layout thrash during drag settle
• perf(ui): keep theme cross-fade gated; document rebuild cost (Fluid F5) #361 F5 — keep theme cross-fade gated; document rebuild cost
• perf(ui): pause work in inactive keep-alive workspace panes (Fluid F6) #362 F6 — pause work in inactive keep-alive workspace panes
• perf(ui): stop update badge pulse ticker when hidden (Fluid F7) #363 F7 — stop update badge pulse ticker when hidden
• perf(ui): narrow ResultsTab mode morph paint scope (Fluid F8) #364 F8 — narrow ResultsTab mode morph paint scope

P2

• chore(motion): tokenize or document remaining magic UI durations (Fluid F9) #365 F9 — tokenize or document remaining magic UI durations
• docs(perf): document Linux refresh_rate query-only behavior (Fluid F10) #366 F10 — document Linux refresh_rate query-only behavior

References

• Obsidian: 12 — Fluid Morphing/Ревью производительности Fluid.md
• Checklist: docs/perf-baseline.md § Fluid shell @ 120 Hz
• Guardrails: docs/motion-and-high-refresh.md, .cursor/rules/querya-motion.mdc
• Related epic: epic(ui): Fluid morphing — evolve QueryaMotion (post-0.4.11 shell) #342

Acceptance (epic)

• All P0 issues closed with tests where applicable
• Manual DevTools pass on Fluid §9–15 at 120 Hz recorded or linked

[ZhuchkaTriplesix]

Created child issues

• perf(ui): isolate tab strip spring rebuilds (Fluid F1) #357
• perf(ui): RepaintBoundary + TickerMode for workspace morph layers (Fluid F2) #358
• perf(ui): stop animating BackdropFilter blur sigma in dialogs (Fluid F3) #359
• perf(ui): reduce split/sidebar layout thrash during drag settle (Fluid F4) #360
• perf(ui): keep theme cross-fade gated; document rebuild cost (Fluid F5) #361
• perf(ui): pause work in inactive keep-alive workspace panes (Fluid F6) #362
• perf(ui): stop update badge pulse ticker when hidden (Fluid F7) #363
• perf(ui): narrow ResultsTab mode morph paint scope (Fluid F8) #364
• chore(motion): tokenize or document remaining magic UI durations (Fluid F9) #365
• docs(perf): document Linux refresh_rate query-only behavior (Fluid F10) #366