feat(ui): align peer count chip with design reference

Mirror the design-doc update in the actual download progress component
so the GUI matches the trimmed chip. Previously the large progress
panel rendered `[icon] from N peer(s)` inline; now it renders just
`[icon] N`, with the full "Downloading from N peers on the LAN"
sentence retained as the `title` tooltip for discoverability.

Changes:
- `DownloadProgress.tsx` (lg variant): drop the "from" / unit text from
  the inline span, keeping only the count. `peerUnit` stays in scope
  because the tooltip still needs singular/plural.
- `launcher.css`: collapse `.dl-peers` and `.dl-peers strong` into a
  single rule that puts the t-1 colour, 600 weight and tabular-nums
  directly on the chip (the inner `<strong>` no longer exists). Gap
  drops from 5px to 4px to match the tighter icon+number layout.
- Container queries: peers drops at <=240px and ETA drops at <=320px,
  matching the new thresholds in the design reference. The narrower
  chip simply fits in smaller modals, so the old 300/380 cutoffs were
  hiding stats that would have rendered fine.

Test Plan
- `just frontend-test` (passes)
- `just run`, start a download, confirm the chip reads `[icon] N`,
  hover shows the tooltip, and narrowing the window collapses ETA
  before peers at the new breakpoints.

crates/lanspread-tauri-deno-ts/src/styles/launcher.css

@@ -1048,14 +1048,11 @@
 .dl-lg-secondary .dl-peers {
   display: inline-flex;
   align-items: center;
-  gap: 5px;
-  color: var(--t-2);
-  white-space: nowrap;
-}
-.dl-lg-secondary .dl-peers strong {
+  gap: 4px;
   color: var(--t-1);
   font-weight: 600;
   font-variant-numeric: tabular-nums;
+  white-space: nowrap;
 }
 .dl-lg-secondary .dl-peers svg {
   opacity: 0.7;
@@ -1069,13 +1066,13 @@
 .dl-sep {
   opacity: 0.45;
 }
-@container (max-width: 380px) {
+@container (max-width: 320px) {
   .dl-lg-secondary .dl-eta,
   .dl-lg-secondary .dl-sep-eta {
     display: none;
   }
 }
-@container (max-width: 300px) {
+@container (max-width: 240px) {
   .dl-lg-secondary .dl-peers,
   .dl-lg-secondary .dl-sep-peers {
     display: none;