Rework the end screen figures, mode picker, corners and race view

End screen
- Every figure is now a dim label directly over its value, the two centred on
  each other, grouped by what they qualify: RAW and PB under WPM, ERR and
  CONSISTENCY under ACC, KEYSTROKES and CHARACTERS either side of TIME. The
  row is a grid so TIME sits on the graph's exact centre line rather than
  drifting with its neighbours' widths.
- Errors go back onto the wpm line. Their own y axis implied a magnitude a
  mistake does not have; what matters is when one happened.
- Graph hover reads "wpm ... raw ... time" - the figures first, the second
  they happened in as the qualifier.

Mode picker
- Opens from the Single Player button itself, and choosing a mode starts it:
  picking what to type and starting it are one action. The control has now
  been a chevron notched into that button, a caption between the two buttons,
  a pill above them and a chip row below them; as the button's own menu it
  needs no separate real estate at all.

Corners
- Settings and Store move to the bottom-left. The top-left is the wordmark's
  alone.
- The global racer count is gone from the home screen - it is not something
  you can act on there. The Friends control carries "N online" instead, which
  is.
- Presence: users gain a last_seen column, touched at most once a minute per
  active user on any authenticated request, and the friends list reports who
  has been seen inside a five-minute window.

Multiplayer race view
- The standings move to the middle of the screen, the space the end screen's
  graph occupies, and now include your own row rather than opponents only.
  Pinned to the top-left corner they put what you are racing against in your
  peripheral vision and left out the one bar you most need to see.

Programming mode
- Snippets carry an explanation of what the code does. Shown under the passage
  while you type in single player; in multiplayer that space belongs to the
  standings, so it waits for the end screen, where it appears either way.

1 files changed, 14 insertions, 6 deletions

diff --git a/web/src/topRail.js b/web/src/topRail.js
index b6b50d7..e8418f6 100644
--- a/web/src/topRail.js
+++ b/web/src/topRail.js
@@ -40,7 +40,8 @@ export function renderTopRail(root, { onShowAccount, onShowFriends, extras = []
     const friends = document.createElement('div');
     friends.className = 'friends-control';
     if (onShowFriends) {
-        friends.innerHTML = `<button class="corner-icon-button has-badge" data-action="rail-friends" aria-label="Friends" data-tooltip="Friends">${FRIENDS_ICON}<span class="rail-badge" data-badge="friends" hidden></span></button>`;
+        friends.innerHTML = `<button class="corner-icon-button" data-action="rail-friends" aria-label="Friends" data-tooltip="Friends">${FRIENDS_ICON}</button>
+                             <span class="online-count" data-badge="friends-online" hidden></span>`;
     }
     wrap.appendChild(friends);
 
@@ -90,11 +91,18 @@ export function renderTopRail(root, { onShowAccount, onShowFriends, extras = []
     // Friends ------------------------------------------------------------
     const friendsBtn = friends.querySelector('[data-action="rail-friends"]');
     if (friendsBtn) friendsBtn.addEventListener('click', onShowFriends);
-    const friendsBadge = friends.querySelector('[data-badge="friends"]');
-    function paintCounts({ friends: friendCount }) {
-        if (!friendsBadge) return;
-        friendsBadge.hidden = !friendCount;
-        friendsBadge.textContent = String(friendCount);
+    // How many friends are online, not how many you have - a total is a fact
+    // about your account, whereas "2 online" is a reason to open the screen.
+    const friendsOnlineEl = friends.querySelector('[data-badge="friends-online"]');
+    function paintCounts({ friends: friendCount, friendsOnline }) {
+        if (friendsBtn) {
+            friendsBtn.dataset.tooltip = !friendCount
+                ? 'Friends'
+                : (friendsOnline ? `Friends - ${friendsOnline} of ${friendCount} online` : `Friends - ${friendCount}, none online`);
+        }
+        if (!friendsOnlineEl) return;
+        friendsOnlineEl.hidden = !friendsOnline;
+        friendsOnlineEl.textContent = `${friendsOnline} online`;
     }
     paintCounts(getCounts());
     const unsubscribeCounts = onCountsChange(paintCounts);