fix(gui): polish sidebar layout, wordmark, tooltip, and fonts to figma

Fixed sidebar width (never concedes), figma session-row rail (16px twist +
status slots, triangle arrows, mount fade), exact brand wordmark svg with
tooltip'd rail controls, form controls inheriting the app font stack, and
inlined the twist button reset since the tsdown CSS pipeline drops composes.

packages/client/ui-primitives/src/index.ts

@@ -14,6 +14,9 @@ export { Menu } from './Menu.tsx'
 export type { MenuItem } from './Menu.tsx'
 export { ConnectionBanner } from './ConnectionBanner.tsx'
 export { FishLogo } from './FishLogo.tsx'
+export { BrandWordmark } from './BrandWordmark.tsx'
+export { Tooltip } from './Tooltip.tsx'
+export type { TooltipSide } from './Tooltip.tsx'
 export { JsonBlock } from './markdown/JsonBlock.tsx'
 export { MessageText } from './markdown/MessageText.tsx'
 export * from './icons/index.tsx'