feat(server): hot-reload config store and reloadable infra clients

- Replace single Load() with a watching Store that re-reads config files
  (and config.local.yaml) and fans out a ReloadEvent with a per-field diff
  so consumers can decide whether the change is hot-applicable or requires
  a process restart.
- Wrap llm, retrieval, vector store, and object storage clients in
  Reloadable* shells so the bootstrap can swap their underlying impls when
  config changes without re-instantiating handlers.
- Make jwt.Manager and ops TokenIssuer mutable under a lock so secrets and
  TTLs can be rotated live; thread default plan code through a setter on
  the ops AdminUserService.
- Wire ConfigStore through bootstrap and every cmd/main.go, scheduler /
  worker / tenant-api / ops-api start the watcher; services and handlers
  take a config.Provider so they always read current values for things
  like generation.stream_enabled, scheduler dispatch, retrieval, etc.
- Switch shared/config decoding off viper to a Kratos-derived runtime
  package so env placeholders (\${VAR:default}) resolve consistently and
  the same source machinery powers both the loader and the watcher.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

server/internal/tenant/app/monitoring_service.go

@@ -9,6 +9,7 @@ import (
 	"fmt"
 	"sort"
 	"strings"
+	"sync"
 	"time"
 
 	"github.com/google/uuid"
@@ -43,6 +44,7 @@ type MonitoringService struct {
 	rabbitMQ                      *rabbitmq.Client
 	redis                         *goredis.Client
 	logger                        *zap.Logger
+	configMu                      sync.RWMutex
 	desktopTasksRolloutPercentage int
 	brandLibraryConfig            config.BrandLibraryConfig
 }
@@ -71,6 +73,25 @@ func (s *MonitoringService) WithRedis(redis *goredis.Client) *MonitoringService
 	return s
 }
 
+func (s *MonitoringService) UpdateConfig(dispatchCfg config.MonitoringDispatchConfig, brandLibraryCfg config.BrandLibraryConfig) {
+	if s == nil {
+		return
+	}
+	s.configMu.Lock()
+	s.desktopTasksRolloutPercentage = dispatchCfg.DesktopTasksRolloutPercentage
+	s.brandLibraryConfig = brandLibraryCfg
+	s.configMu.Unlock()
+}
+
+func (s *MonitoringService) currentConfig() (int, config.BrandLibraryConfig) {
+	if s == nil {
+		return 0, config.BrandLibraryConfig{}
+	}
+	s.configMu.RLock()
+	defer s.configMu.RUnlock()
+	return s.desktopTasksRolloutPercentage, s.brandLibraryConfig
+}
+
 type MonitoringDashboardCompositeResponse struct {
 	Overview          MonitoringOverview          `json:"overview"`
 	Runtime           MonitoringDashboardRuntime  `json:"runtime"`