docs(web-ui): update CSS bundle description for split stylesheet layout

docs/web-ui/shape.md

@@ -15,7 +15,9 @@
 - `GET /static/*` → bundled CSS + JS produced by esbuild
   (`frontend/packages/{dashboard,agent}/build.mjs`). Both pages
   pull the shared terminal pane + Catppuccin palette + typography
-  from `@hive/shared` (was `hive-fr0nt`); the CSS bundle inlines
+  from `@hive/shared` (was `hive-fr0nt`); the dashboard ships four
+  CSS bundles (`common.css` loaded by every page, plus per-page
+  `dashboard.css` / `flow.css` / `logs.css`); `common.css` inlines
   `base.css` + `terminal.css` via esbuild's `@import` resolution.
   `terminal.js` exports `{ create, linkify }` as ES module
   members (no more `window.HiveTerminal` global outside the