fix: clarify c removes from the list, never your files

Reword the c help labels (Downloads "Cancel or remove from list", Seeding
"Remove from list", dropping the Downloads cross-reference) and add a help
note that downloaded files always stay on disk, so cancel and remove never
read as deleting your media. Also trims the over-specific c sentence from the
readme and refreshes the npm description and keywords.

src/ui/components/HelpOverlay.tsx

@@ -54,7 +54,8 @@ export function HelpOverlay() {
           </Box>
         ))}
       </Box>
-      <Box marginTop={1}>
+      <Box marginTop={1} flexDirection="column">
+        <Text dimColor>Your downloaded files always stay on disk.</Text>
         <Text dimColor>Press ? or esc to close</Text>
       </Box>
     </Box>