feat: move projects to sidebar rail and speed up session switching (#506)

* feat: move projects from header tabs to left sidebar rail

* refactor: remove variant from git generation session context

* feat: implemented drandrop action for navrails

* refactor: improve sidebar drag-and-drop smoothness and remove floating overlay

* fix: prevent mobile nav rail touch from closing drawer and opening menu

* fix: hide header tabs on desktop

* fix: prevent session flicker when switching projects

* style: soften chat panel divider borders

* style: improve icon contrast across core navigation

* fix: stabilize session selection during project switching

* style: unify sidebar surfaces and transparent section layers

* style: remove UI shadows and keep only scroll shadow

* perf: speed up project switching with cached session loading

* perf: speed up Git changes view and background refresh

* perf: make session switching lighter and less aggressive

* perf: optimized sessions list loading while project switching

* perf: smooth chat rendering and reduce interaction spikes

* fix: restore reliable load older messages visibility

packages/ui/src/styles/fireworks.css

@@ -33,7 +33,6 @@
   height: var(--particle-size, 6px);
   border-radius: 999px;
   background: var(--firework-color, var(--status-success));
-  box-shadow: 0 0 12px rgba(255, 255, 255, 0.25);
   opacity: 0;
   transform: translate(-50%, -50%) scale(0.4);
   animation: firework-pop var(--firework-duration, var(--fireworks-duration-ms)) ease-out forwards;