docs: the ⌘K palette description matches what it actually offers (BEA-84) (#132)

README.md:499 promised "share/history/upload actions" in the command
palette. Upload has never existed there (browser upload is deliberately
absent, Browser.tsx:175), download went unmentioned, and share/download
are file-scoped — so a reader on a folder route goes hunting for controls
that are correctly hidden. The doc comment at Palette.tsx:8 carried the
same wrong list, so fixing only the README would leave the next reader of
the component with the same picture.

Prose and a comment only; no code path changes. `npm run build` produces
a byte-identical internal/webapp/static (source comments are stripped
from the bundle), so no assets to commit.

Co-authored-by: Claude Opus 5 (1M context) <noreply@anthropic.com>

internal/webapp/frontend/src/components/Palette.tsx

@@ -5,7 +5,7 @@ import { Dialog, DialogContent, DialogTitle } from "@/components/ui/dialog";
 
 /* ---- command palette (⌘K / Ctrl+K) ----
    One box for everything: fuzzy-jump to any file, switch projects, and run
-   quick actions (share, history, upload, download, sign out). */
+   quick actions (history always, share and download on a file, sign out). */
 
 export interface PaletteItem {
   icon: string;