docs: add example programs for common usage patterns (#19)

Adds four focused examples in examples/ directory:
- basic: drop-in logger with web UI
- namespaces: namespace-based logging by component
- client: programmatic log client with filtering
- log-levels: all log levels and filtering

Fixes #7

examples/namespaces/main.go

@@ -0,0 +1,73 @@
+// Example: namespace-based logging for organizing logs by component.
+//
+// Namespaces let you tag log entries by subsystem (api, database, auth, etc.)
+// and filter them in the web UI or via programmatic clients.
+package main
+
+import (
+	"fmt"
+	"math/rand"
+	"net/http"
+	"time"
+
+	"github.com/taigrr/log-socket/v2/browser"
+	logger "github.com/taigrr/log-socket/v2/log"
+	"github.com/taigrr/log-socket/v2/ws"
+)
+
+func main() {
+	defer logger.Flush()
+
+	// Create loggers for different subsystems
+	apiLog := logger.NewLogger("api")
+	dbLog := logger.NewLogger("database")
+	authLog := logger.NewLogger("auth")
+	cacheLog := logger.NewLogger("cache")
+
+	// Simulate application activity
+	go func() {
+		for {
+			apiLog.Infof("GET /api/users — 200 OK (%dms)", rand.Intn(200))
+			apiLog.Debugf("Request headers: Accept=application/json")
+			time.Sleep(1 * time.Second)
+		}
+	}()
+
+	go func() {
+		for {
+			dbLog.Infof("SELECT * FROM users — %d rows", rand.Intn(100))
+			if rand.Float64() < 0.3 {
+				dbLog.Warn("Slow query detected (>500ms)")
+			}
+			time.Sleep(2 * time.Second)
+		}
+	}()
+
+	go func() {
+		for {
+			if rand.Float64() < 0.7 {
+				authLog.Info("User login successful")
+			} else {
+				authLog.Error("Failed login attempt from 192.168.1.42")
+			}
+			time.Sleep(3 * time.Second)
+		}
+	}()
+
+	go func() {
+		for {
+			cacheLog.Tracef("Cache hit ratio: %.1f%%", rand.Float64()*100)
+			if rand.Float64() < 0.1 {
+				cacheLog.Warn("Cache eviction triggered")
+			}
+			time.Sleep(5 * time.Second)
+		}
+	}()
+
+	// The /api/namespaces endpoint lists all active namespaces
+	http.HandleFunc("/ws", ws.LogSocketHandler)
+	http.HandleFunc("/api/namespaces", ws.NamespacesHandler)
+	http.HandleFunc("/", browser.LogSocketViewHandler)
+	fmt.Println("Log viewer with namespace filtering at http://localhost:8080")
+	logger.Fatal(http.ListenAndServe("0.0.0.0:8080", nil))
+}