Add iOS debug bundle support in Go

Thread cacheDir through NewClient -> RunOniOS -> MobileDependency.TempDir
so the iOS client can pass its sandbox-writable cache directory for
debug bundle zip file creation instead of os.TempDir().

Move log collection into platform-dispatched addPlatformLog():
- iOS: adds the file-based Go client log (with rotation, stderr/stdout
  companions and anonymization handled by addLogfile) plus the Swift app
  log (swift-log.log) written by the iOS app into the same log directory
- Other non-Android platforms: existing file-based log + systemd fallback

Narrow the debug_nonandroid.go build tag to !android && !ios so iOS no
longer attempts the systemd journal fallback.

Add a DebugBundle() entry point to the iOS Go client that generates a
bundle, uploads it and returns the upload key. It works with or without
a running engine: when the engine is up it reuses the live config, sync
response and client metrics; otherwise it loads the config from disk (or
the preloaded tvOS config). Guard the live config/ConnectClient behind a
state mutex since DebugBundle may run on a different thread.

client/internal/debug/debug_ios.go

@@ -0,0 +1,36 @@
+//go:build ios
+
+package debug
+
+import (
+	"path/filepath"
+
+	log "github.com/sirupsen/logrus"
+)
+
+// swiftLogFile is the Swift app log written by the iOS app into the same log
+// directory as the Go client log, so it can be collected into the bundle.
+const swiftLogFile = "swift-log.log"
+
+// addPlatformLog collects logs for the iOS debug bundle. iOS has no logcat or
+// systemd journal, so we rely on file-based logs. addLogfile handles the Go
+// client log (logPath) with rotation, the stderr/stdout companions and
+// anonymization. The iOS app writes its own Swift log into the same directory,
+// so we add it alongside the Go log.
+func (g *BundleGenerator) addPlatformLog() error {
+	if err := g.addLogfile(); err != nil {
+		return err
+	}
+
+	if g.logPath == "" {
+		return nil
+	}
+
+	swiftLogPath := filepath.Join(filepath.Dir(g.logPath), swiftLogFile)
+	if err := g.addSingleLogfile(swiftLogPath, swiftLogFile); err != nil {
+		// The Swift log is best-effort: the app may not have written it yet.
+		log.Warnf("failed to add %s to debug bundle: %v", swiftLogFile, err)
+	}
+
+	return nil
+}

client/internal/debug/debug_nonandroid.go

@@ -1,4 +1,4 @@
-//go:build !android
+//go:build !android && !ios
 
 package debug