test(hotreload): increase caddytest's Client.Timeout (#2431)

## Root cause

`TestHotReload` was failing on
https://github.com/php/frankenphp/actions/runs/25961840516/job/76318473726
(`linux/arm/v7`, dispatched from
#2430) with:

> context deadline exceeded (Client.Timeout or context cancellation
while reading body)

`caddytest.NewTester` initialises `tester.Client.Timeout = 5s`
(`Default.TestRequestTimeout`). That budget covers the entire roundtrip
including body reads. On an emulated armv7 runner the chain
`os.WriteFile` → e-dant/watcher event → `mercure` publish → SSE chunk
delivery doesn't complete in 5 s, so the streaming `resp.Body.Read` is
killed before the marker `index.php` is seen. The job died at exactly
5.03 s.

## Fix

Set `tester.Client.Timeout = 0` for this test. The test already cancels
the read via `context.WithCancel` once the marker appears in the buffer,
and Go's `-timeout` provides the outer deadline — the 5 s inner cap was
redundant.

The other failing job on that run (`linux/amd64`, e-dant/watcher cmake
build) is unrelated to this PR.

Author: dunglas

caddy/hotreload_test.go

@@ -11,6 +11,7 @@ import (
 	"strings"
 	"sync"
 	"testing"
+	"time"
 
 	"github.com/caddyserver/caddy/v2/caddytest"
 	"github.com/stretchr/testify/require"
@@ -25,6 +26,10 @@ func TestHotReload(t *testing.T) {
 	indexFile := filepath.Join(tmpDir, "index.php")
 
 	tester := caddytest.NewTester(t)
+	// caddytest's default 5s http.Client.Timeout is too tight for the
+	// SSE roundtrip below on slow CI runners (notably emulated armv7).
+	// 30s keeps the test bounded so a real regression fails fast.
+	tester.Client.Timeout = 30 * time.Second
 	tester.InitServer(`
 		{
 			debug