refactor: update AppShell and sidebar components for improved design consistency

Removed unused utility functions from the AppShell component and updated the sidebar width to a fixed value for better layout control. Revised the UI design documentation to clarify the shared App Shell chrome specifications and ensure alignment with design standards. Enhanced the sidebar configuration to reflect the new width and styling guidelines.

docs/ui-design-contract.md

@@ -50,18 +50,22 @@ Gating: KV `ui_show_quick_actions` in `global_settings` via `PATCH /v1/settings`
 
 ## Shared App Shell chrome
 
-Эталон: CFDM + ReUI [app-shell-12](https://reui.io/preview/base/app-shell-12) · monitor/switchers [app-shell-7](https://reui.io/preview/base/app-shell-7).
+Эталон: **EvoBGP** production [`apps/web/src/components/layout/app-shell.tsx`](../apps/web/src/components/layout/app-shell.tsx) + ReUI [app-shell-12](https://reui.io/preview/base/app-shell-12).
 
-При переключении между vps-tracker / CFDM / EvoBGP меняются **только** sidebar nav и `main` content. ClassNames chrome идентичны.
+При переключении между vps-tracker / CFDM / EvoBGP меняются **только** sidebar nav labels/hrefs и `main` content. Разметка, ширина, фон и hover chrome идентичны.
 
 | Токен / зона | Значение |
 |--------------|----------|
-| `--sidebar-width` | `240px` |
-| Sidebar accent | primary **14%** mix + transparent border |
-| Header | `h-12`, `sticky`, `border-b`, `px-4 md:px-6` (без blur / без `h-16`) |
-| Header right | **AppsMenu** → **SystemMonitorPopover** → **ModeToggle** |
+| `SIDEBAR_WIDTH` / `--sidebar-width` | `240px` (в `packages/ui` sidebar + Provider style) |
+| Sidebar / hover colors | theme `--sidebar` / `--sidebar-accent` из `globals.css` — **без** AppShell `color-mix` override |
+| Header | `h-12`, `sticky`, `border-b`, `px-4 md:px-6` |
+| Header left | `SidebarTrigger` + `Separator` + Breadcrumb |
+| Header right | **AppsMenu** → **SystemMonitorPopover** → **ModeToggle** (без Search в chrome) |
+| Sidebar | AppSwitcher → groups (`SidebarGroupContent`) → icons `size-4` → **пустой** `SidebarFooter` |
 | `main` | `gap-4 md:gap-6`, `px-4 py-4 md:px-6 md:py-5` |
-| Sidebar header | `AppSwitcher` (не static brand) |
+| Search | hotkey ⌘K / Ctrl+K only (не кнопка в header) |
+
+Запрещено в chrome: `SidebarRail`, `NavUser` footer, sync-row footer, Search/Ctrl+K pill в header, issues Badge в header, muted/hover cascade на right-cluster, Provider `color-mix` для `--sidebar*`.
 
 App Switcher ids: `vps-tracker` · `cfdm` · `evobgp`. Override: `VITE_APP_SWITCHER` JSON.