feat: add Redirect and ReplaceURL methods for browser navigation

Add SSE-based navigation methods to Context:
- Redirect(url) / Redirectf() - navigate to new page
- ReplaceURL(url) / ReplaceURLf() - update URL without navigation

Update session example to demonstrate full login flow with redirects.

context.go

@@ -318,6 +318,37 @@ func (c *Context) ExecScript(s string) {
 	c.sendPatch(patch{patchTypeScript, s})
 }
 
+// Redirect navigates the browser to the given URL.
+// This triggers a full page navigation - the current context will be disposed
+// and a new context created at the destination URL.
+func (c *Context) Redirect(url string) {
+	if url == "" {
+		c.app.logWarn(c, "redirect failed: empty url")
+		return
+	}
+	c.sendPatch(patch{patchTypeRedirect, url})
+}
+
+// Redirectf navigates the browser to a URL constructed from the format string and arguments.
+func (c *Context) Redirectf(format string, a ...any) {
+	c.Redirect(fmt.Sprintf(format, a...))
+}
+
+// ReplaceURL updates the browser's URL and history without triggering navigation.
+// Useful for updating query params or path to reflect UI state changes.
+func (c *Context) ReplaceURL(url string) {
+	if url == "" {
+		c.app.logWarn(c, "replace url failed: empty url")
+		return
+	}
+	c.sendPatch(patch{patchTypeReplaceURL, url})
+}
+
+// ReplaceURLf updates the browser's URL using a format string.
+func (c *Context) ReplaceURLf(format string, a ...any) {
+	c.ReplaceURL(fmt.Sprintf(format, a...))
+}
+
 // stopAllRoutines stops all go routines tied to this Context preventing goroutine leaks.
 func (c *Context) stopAllRoutines() {
 	select {

internal/examples/session/main.go

@@ -7,11 +7,11 @@ import (
 
 func main() {
 	v := via.New()
+	v.Config(via.Options{ServerAddress: ":7331"})
 
-	v.Page("/", func(c *via.Context) {
-		username := c.Session().GetString("username")
+	// Login page
+	v.Page("/login", func(c *via.Context) {
 		flash := c.Session().PopString("flash")
-
 		usernameInput := c.Signal("")
 
 		login := c.Action(func() {
@@ -20,38 +20,69 @@ func main() {
 				c.Session().Set("username", name)
 				c.Session().Set("flash", "Welcome, "+name+"!")
 				c.Session().RenewToken()
+				c.Redirect("/dashboard")
 			}
-			c.Sync()
-		})
-
-		logout := c.Action(func() {
-			c.Session().Set("flash", "Goodbye!")
-			c.Session().Delete("username")
-			c.Sync()
 		})
 
 		c.View(func() h.H {
+			// Already logged in? Redirect to dashboard
+			if c.Session().GetString("username") != "" {
+				c.Redirect("/dashboard")
+				return h.Div()
+			}
+
 			var flashMsg h.H
 			if flash != "" {
 				flashMsg = h.P(h.Text(flash), h.Style("color: green"))
 			}
+			return h.Div(
+				flashMsg,
+				h.H1(h.Text("Login")),
+				h.Input(h.Type("text"), h.Placeholder("Username"), usernameInput.Bind()),
+				h.Button(h.Text("Login"), login.OnClick()),
+			)
+		})
+	})
 
+	// Dashboard page (protected)
+	v.Page("/dashboard", func(c *via.Context) {
+		logout := c.Action(func() {
+			c.Session().Set("flash", "Goodbye!")
+			c.Session().Delete("username")
+			c.Redirect("/login")
+		})
+
+		c.View(func() h.H {
+			username := c.Session().GetString("username")
+
+			// Not logged in? Redirect to login
 			if username == "" {
-				return h.Div(
-					flashMsg,
-					h.H1(h.Text("Login")),
-					h.Input(h.Type("text"), h.Placeholder("Username"), usernameInput.Bind()),
-					h.Button(h.Text("Login"), login.OnClick()),
-				)
+				c.Session().Set("flash", "Please log in first")
+				c.Redirect("/login")
+				return h.Div()
+			}
+
+			flash := c.Session().PopString("flash")
+			var flashMsg h.H
+			if flash != "" {
+				flashMsg = h.P(h.Text(flash), h.Style("color: green"))
 			}
 			return h.Div(
 				flashMsg,
-				h.H1(h.Textf("Hello, %s!", username)),
+				h.H1(h.Textf("Dashboard - Hello, %s!", username)),
 				h.P(h.Text("Your session persists across page refreshes.")),
 				h.Button(h.Text("Logout"), logout.OnClick()),
 			)
 		})
 	})
 
+	// Redirect root to login
+	v.Page("/", func(c *via.Context) {
+		c.View(func() h.H {
+			c.Redirect("/login")
+			return h.Div()
+		})
+	})
+
 	v.Start()
 }

via.go

@@ -15,6 +15,7 @@ import (
 	"io"
 	"log"
 	"net/http"
+	"net/url"
 	"os"
 	"path/filepath"
 	"strings"
@@ -359,6 +360,8 @@ const (
 	patchTypeElements = iota
 	patchTypeSignals
 	patchTypeScript
+	patchTypeRedirect
+	patchTypeReplaceURL
 )
 
 type patch struct {
@@ -453,6 +456,21 @@ func New() *V {
 							v.logErr(c, "ExecuteScript failed: %v", err)
 						}
 					}
+				case patchTypeRedirect:
+					if err := sse.Redirect(patch.content); err != nil {
+						if sse.Context().Err() == nil {
+							v.logErr(c, "Redirect failed: %v", err)
+						}
+					}
+				case patchTypeReplaceURL:
+					parsedURL, err := url.Parse(patch.content)
+					if err != nil {
+						v.logErr(c, "ReplaceURL failed to parse URL: %v", err)
+					} else if err := sse.ReplaceURL(*parsedURL); err != nil {
+						if sse.Context().Err() == nil {
+							v.logErr(c, "ReplaceURL failed: %v", err)
+						}
+					}
 				}
 			}
 		}