feat: season leaderboard with toggle and countdown

Add GET /api/bots/leaderboard?season=current endpoint. LeaderboardPage
now toggles between "This Season" and "All Time" views. Shows season
name, countdown timer, and top 3 placement badges.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

server/src/routes/bots.ts

@@ -149,6 +149,49 @@ botsRouter.get('/:name', async (c) => {
 })
 
 // Get bot stats -- full account page data
+
+// Season leaderboard endpoint
+botsRouter.get('/leaderboard', async (c) => {
+  const seasonParam = c.req.query('season')
+
+  if (seasonParam === 'current' || seasonParam) {
+    const { getCurrentSeason, getSeasonLeaderboard, getSeasonById } = await import('../engine/seasons.js')
+    const season = seasonParam === 'current' ? getCurrentSeason() : getSeasonById(seasonParam)
+    if (!season) return c.json({ error: 'Season not found' }, 404)
+    const entries = await getSeasonLeaderboard(season.id)
+    return c.json({ season, entries })
+  }
+
+  // All-time: fall through to default bot list sorted by Elo
+  const allBots = await db.select({
+    id: schema.bots.id,
+    name: schema.bots.name,
+    avatarSeed: schema.bots.avatarSeed,
+    archetype: schema.bots.archetype,
+    eloRating: schema.bots.eloRating,
+    wins: schema.bots.wins,
+    losses: schema.bots.losses,
+    winStreak: schema.bots.winStreak,
+    tier: schema.bots.tier,
+    botType: schema.bots.botType,
+  }).from(schema.bots)
+
+  const ranked = allBots.filter(b => b.botType !== 'classic')
+  ranked.sort((a, b) => b.eloRating - a.eloRating)
+
+  return c.json({ season: null, entries: ranked.map(b => ({
+    botId: b.id,
+    botName: b.name,
+    archetype: b.archetype,
+    tier: b.tier,
+    wins: b.wins,
+    losses: b.losses,
+    eloRating: b.eloRating,
+    avatarSeed: b.avatarSeed,
+    winStreak: b.winStreak,
+  })) })
+})
+
 botsRouter.get('/:name/stats', async (c) => {
   const name = c.req.param('name')
   const ownerPubkey = c.req.query('pubkey')