feat: comprehensive debug logging across all controller modules

Add detailed [DEBUG] logging to every controller module when
logging.level is set to "debug". Each module with stateful debug
uses SetDebug(bool) wired from main.go. Covers stacks, backup,
cloudflare, integrations, system, monitor, settings, scheduler,
web handlers, storage, metrics, API, selfupdate, and assets.

Also includes the app export/import (.fab bundles) feature from
v0.32.0 and its debug page integration.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

controller/internal/backup/appdata.go

@@ -89,7 +89,7 @@ func DiscoverAppData(provider StackDataProvider, discoveredDBs []DiscoveredDB) [
 		info.HasHDDData = len(info.HDDPaths) > 0
 
 		// Discover Docker named volumes from compose
-		info.DockerVolumes = parseComposeNamedVolumes(stack.ComposePath)
+		info.DockerVolumes = ParseComposeNamedVolumes(stack.ComposePath)
 
 		// Check if app has a DB container (already backed up via DB dump)
 		for _, db := range discoveredDBs {
@@ -108,8 +108,8 @@ func DiscoverAppData(provider StackDataProvider, discoveredDBs []DiscoveredDB) [
 	return result
 }
 
-// parseComposeNamedVolumes extracts named Docker volumes from a docker-compose.yml.
-func parseComposeNamedVolumes(composePath string) []AppDockerVolume {
+// ParseComposeNamedVolumes extracts named Docker volumes from a docker-compose.yml.
+func ParseComposeNamedVolumes(composePath string) []AppDockerVolume {
 	data, err := os.ReadFile(composePath)
 	if err != nil {
 		return nil