feat: maintenance flows frontend foundation - types, API clients, sidebar, library filter

- Add maintenance.ts types: TargetEntry, TargetList, MaintenanceSchedule, BatchLaunch
- Add targetListsApi and maintenanceSchedulesApi/batchLaunchApi clients
- Extend TreeType union with 'maintenance' in tree.ts
- Update getTreeNavigatePath/getTreeEditorPath in routing.ts for maintenance
- Sidebar: track maintenance count and add Maintenance sub-nav item
- TreeLibraryPage: add maintenance to typeFilter state, URL sync, and tab buttons
- TreeGridView, TreeListView, TreeTableView: add amber Wrench maintenance badge

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

frontend/src/types/index.ts

@@ -23,3 +23,14 @@ export interface PaginatedResponse<T> {
 export interface ApiError {
   detail: string
 }
+
+export type {
+  TargetEntry,
+  TargetList,
+  TargetListCreate,
+  MaintenanceSchedule,
+  MaintenanceScheduleCreate,
+  MaintenanceScheduleUpdate,
+  BatchLaunchRequest,
+  BatchLaunchResponse,
+} from './maintenance'

frontend/src/types/maintenance.ts

@@ -0,0 +1,65 @@
+export interface TargetEntry {
+  label: string
+  notes?: string
+}
+
+export interface TargetList {
+  id: string
+  team_id: string
+  created_by?: string
+  name: string
+  description?: string
+  targets: TargetEntry[]
+  created_at: string
+  updated_at: string
+}
+
+export interface TargetListCreate {
+  name: string
+  description?: string
+  targets: TargetEntry[]
+}
+
+export interface MaintenanceSchedule {
+  id: string
+  tree_id: string
+  created_by?: string
+  cron_expression: string
+  timezone: string
+  target_list_id?: string
+  is_active: boolean
+  next_run_at?: string
+  last_run_at?: string
+  created_at: string
+  updated_at: string
+}
+
+export interface MaintenanceScheduleCreate {
+  tree_id: string
+  cron_expression: string
+  timezone: string
+  target_list_id?: string
+}
+
+export interface MaintenanceScheduleUpdate {
+  cron_expression?: string
+  timezone?: string
+  target_list_id?: string
+  is_active?: boolean
+}
+
+export interface BatchLaunchRequest {
+  tree_id: string
+  targets: TargetEntry[]
+}
+
+export interface BatchLaunchResponse {
+  batch_id: string
+  count: number
+  sessions: Array<{
+    id: string
+    batch_id: string
+    target_label: string
+    tree_id: string
+  }>
+}

frontend/src/types/tree.ts

@@ -58,7 +58,7 @@ export interface TreeStructure {
 
 // --- Procedural Flow Types ---
 
-export type TreeType = 'troubleshooting' | 'procedural'
+export type TreeType = 'troubleshooting' | 'procedural' | 'maintenance'
 
 export type IntakeFieldType =
   | 'text' | 'textarea' | 'number' | 'ip_address' | 'email' | 'url'