refactor: remove realtime visitors detail page

Remove the individual session journey page and make the live visitor
count a static indicator. Prepares for the new aggregated User Journeys
feature (v0.17).

lib/api/realtime.ts

@@ -1,42 +0,0 @@
-import apiRequest from './client'
-
-export interface Visitor {
-  session_id: string
-  first_seen: string
-  last_seen: string
-  pageviews: number
-  current_path: string
-  browser: string
-  os: string
-  device_type: string
-  country: string
-  city: string
-}
-
-export interface SessionEvent {
-  id: string
-  site_id: string
-  session_id: string
-  path: string
-  referrer: string | null
-  user_agent: string
-  country: string | null
-  city: string | null
-  region: string | null
-  device_type: string
-  screen_resolution: string | null
-  browser: string | null
-  os: string | null
-  timestamp: string
-  created_at: string
-}
-
-export async function getRealtimeVisitors(siteId: string): Promise<Visitor[]> {
-  const data = await apiRequest<{ visitors: Visitor[] }>(`/sites/${siteId}/realtime/visitors`)
-  return data.visitors
-}
-
-export async function getSessionDetails(siteId: string, sessionId: string): Promise<SessionEvent[]> {
-  const data = await apiRequest<{ events: SessionEvent[] }>(`/sites/${siteId}/sessions/${sessionId}`)
-  return data.events
-}

lib/hooks/useRealtimeSSE.ts

@@ -1,53 +0,0 @@
-// * SSE hook for real-time visitor streaming.
-// * Replaces 5-second polling with a persistent EventSource connection.
-// * The backend broadcasts one DB query per site to all connected clients,
-// * so 1,000 users on the same site share a single query instead of each
-// * triggering their own.
-
-import { useEffect, useRef, useState, useCallback } from 'react'
-import { API_URL } from '@/lib/api/client'
-import type { Visitor } from '@/lib/api/realtime'
-
-interface UseRealtimeSSEReturn {
-  visitors: Visitor[]
-  connected: boolean
-}
-
-export function useRealtimeSSE(siteId: string): UseRealtimeSSEReturn {
-  const [visitors, setVisitors] = useState<Visitor[]>([])
-  const [connected, setConnected] = useState(false)
-  const esRef = useRef<EventSource | null>(null)
-
-  // Stable callback so we don't recreate EventSource on every render
-  const handleMessage = useCallback((event: MessageEvent) => {
-    try {
-      const data = JSON.parse(event.data)
-      setVisitors(data.visitors || [])
-    } catch {
-      // Ignore malformed messages
-    }
-  }, [])
-
-  useEffect(() => {
-    if (!siteId) return
-
-    const url = `${API_URL}/api/v1/sites/${siteId}/realtime/stream`
-    const es = new EventSource(url, { withCredentials: true })
-    esRef.current = es
-
-    es.onopen = () => setConnected(true)
-    es.onmessage = handleMessage
-    es.onerror = () => {
-      setConnected(false)
-      // EventSource auto-reconnects with exponential backoff
-    }
-
-    return () => {
-      es.close()
-      esRef.current = null
-      setConnected(false)
-    }
-  }, [siteId, handleMessage])
-
-  return { visitors, connected }
-}