fix: stabilize maintenance flow run/resume and procedural scrolling

frontend/src/lib/routing.ts

@@ -5,7 +5,7 @@
  */
 
 /**
- * Get the navigation path for starting or resuming a tree/session.
+ * Get the default navigation path for starting a flow from the library.
  */
 export function getTreeNavigatePath(
   treeId: string,
@@ -20,6 +20,20 @@ export function getTreeNavigatePath(
   return `/trees/${treeId}/navigate`
 }
 
+/**
+ * Get the navigation path for resuming an existing session.
+ * Maintenance and procedural sessions both resume in procedural navigation.
+ */
+export function getSessionResumePath(
+  treeId: string,
+  treeType?: string
+): string {
+  if (treeType === 'procedural' || treeType === 'maintenance') {
+    return `/flows/${treeId}/navigate`
+  }
+  return `/trees/${treeId}/navigate`
+}
+
 /**
  * Get the editor path for a tree.
  */

frontend/src/pages/MaintenanceFlowDetailPage.tsx

@@ -23,6 +23,11 @@ export default function MaintenanceFlowDetailPage() {
     const load = async () => {
       try {
         const treeData = await treesApi.get(id)
+        if (treeData.tree_type !== 'maintenance') {
+          toast.error('This page is only for maintenance flows')
+          navigate('/trees?type=maintenance')
+          return
+        }
         setTree(treeData)
 
         // Load recent sessions for this tree

frontend/src/pages/ProceduralNavigationPage.tsx

@@ -97,7 +97,7 @@ export function ProceduralNavigationPage() {
     setIsLoading(true)
     try {
       const treeData = await treesApi.get(id)
-      if (treeData.tree_type !== 'procedural') {
+      if (treeData.tree_type !== 'procedural' && treeData.tree_type !== 'maintenance') {
         navigate(`/trees/${id}/navigate`, { replace: true })
         return
       }
@@ -116,7 +116,7 @@ export function ProceduralNavigationPage() {
         await startSession(id, {})
       }
     } catch {
-      toast.error('Failed to load procedure')
+      toast.error('Failed to load flow')
       navigate('/my-trees')
     } finally {
       setIsLoading(false)
@@ -340,7 +340,7 @@ export function ProceduralNavigationPage() {
   const currentStepState = currentStep ? stepStates.get(currentStep.id) : undefined
 
   return (
-    <div className="flex h-full flex-col">
+    <div className="flex h-full min-h-0 flex-col">
       {/* Top bar */}
       <div className="border-b border-border px-4 py-3 sm:px-6">
         <div className="flex items-center justify-between gap-4">
@@ -370,8 +370,8 @@ export function ProceduralNavigationPage() {
         {/* Left sidebar - step checklist */}
         <div
           className={cn(
-            'border-r border-border bg-card transition-all duration-200',
-            sidebarOpen ? 'w-72 p-3' : 'w-0 overflow-hidden p-0'
+            'min-h-0 border-r border-border bg-card transition-all duration-200',
+            sidebarOpen ? 'w-72 overflow-y-auto p-3' : 'w-0 overflow-hidden p-0'
           )}
         >
           {sidebarOpen && (

frontend/src/pages/SessionHistoryPage.tsx

@@ -8,7 +8,7 @@ import { SessionFilters } from '@/components/session/SessionFilters'
 import type { SessionFilterState } from '@/components/session/SessionFilters'
 import { cn } from '@/lib/utils'
 import { toast } from '@/lib/toast'
-import { getTreeNavigatePath } from '@/lib/routing'
+import { getSessionResumePath } from '@/lib/routing'
 
 export function SessionHistoryPage() {
   const navigate = useNavigate()
@@ -285,7 +285,7 @@ export function SessionHistoryPage() {
                   </button>
                   {!session.completed_at && (
                     <button
-                      onClick={() => navigate(getTreeNavigatePath(session.tree_id, session.tree_snapshot?.tree_type), { state: { sessionId: session.id } })}
+                      onClick={() => navigate(getSessionResumePath(session.tree_id, session.tree_snapshot?.tree_type), { state: { sessionId: session.id } })}
                       className={cn(
                         'rounded-md bg-gradient-brand px-3 py-2 text-sm font-medium text-white shadow-lg shadow-primary/20',
                         'hover:opacity-90'

frontend/src/pages/TreeLibraryPage.tsx

@@ -14,7 +14,7 @@ import { TreeTableView } from '@/components/library/TreeTableView'
 import { ViewToggle } from '@/components/library/ViewToggle'
 import { SortDropdown } from '@/components/library/SortDropdown'
 import { cn, safeGetItem } from '@/lib/utils'
-import { getTreeNavigatePath } from '@/lib/routing'
+import { getSessionResumePath } from '@/lib/routing'
 import { usePermissions } from '@/hooks/usePermissions'
 import { useUserPreferencesStore } from '@/store/userPreferencesStore'
 import { toast } from '@/lib/toast'
@@ -425,7 +425,7 @@ export function TreeLibraryPage() {
                   </div>
                   <div className="flex items-center gap-2">
                     <button
-                      onClick={() => navigate(getTreeNavigatePath(s.tree_id, s.tree_snapshot?.tree_type), { state: { sessionId: s.id } })}
+                      onClick={() => navigate(getSessionResumePath(s.tree_id, s.tree_snapshot?.tree_type), { state: { sessionId: s.id } })}
                       className="flex items-center gap-1.5 rounded-md bg-gradient-brand px-3 py-1.5 text-sm font-medium text-white shadow-lg shadow-primary/20 hover:opacity-90"
                     >
                       <Play className="h-3.5 w-3.5" />