feat: update frontend type definitions and status enums to match new backend

- types/index.ts: Task status 'progressing' → 'undergoing' + 'completed'; Milestone status updated to open/freeze/undergoing/completed/closed + started_at field
- MilestoneFormModal: dropdown options updated
- MilestoneDetailPage: isProgressing → isUndergoing, badge class simplified
- MilestonesPage: badge class simplified
- TaskDetailPage: status transition map updated for new state machine

src/components/MilestoneFormModal.tsx

@@ -125,9 +125,9 @@ export default function MilestoneFormModal({ isOpen, onClose, onSaved, milestone
               Status
               <select value={form.status} onChange={(e) => setForm((f) => ({ ...f, status: e.target.value }))}>
                 <option value="open">Open</option>
-                <option value="pending">Pending</option>
-                <option value="deferred">Deferred</option>
-                <option value="progressing">Progressing</option>
+                <option value="freeze">Freeze</option>
+                <option value="undergoing">Undergoing</option>
+                <option value="completed">Completed</option>
                 <option value="closed">Closed</option>
               </select>
             </label>

src/pages/MilestoneDetailPage.tsx

@@ -96,7 +96,7 @@ export default function MilestoneDetailPage() {
     currentMemberRole === 'admin'
   ))
 
-  const isProgressing = milestone?.status === 'progressing'
+  const isUndergoing = milestone?.status === 'undergoing'
 
   if (!milestone) return <div className="loading">Loading...</div>
 
@@ -117,7 +117,7 @@ export default function MilestoneDetailPage() {
       <div className="task-header">
         <h2>🏁 {milestone.title}</h2>
         <div className="task-meta">
-          <span className={`badge status-${milestone.status === 'progressing' ? 'in_progress' : milestone.status}`}>{milestone.status}</span>
+          <span className={`badge status-${milestone.status}`}>{milestone.status}</span>
           {milestone.due_date && <span className="text-dim">Due {dayjs(milestone.due_date).format('YYYY-MM-DD')}</span>}
           {milestone.planned_release_date && <span className="text-dim">Planned Release: {dayjs(milestone.planned_release_date).format('YYYY-MM-DD')}</span>}
         </div>
@@ -154,14 +154,14 @@ export default function MilestoneDetailPage() {
 
       <div className="section">
         <div style={{ display: 'flex', gap: 8, marginBottom: 16 }}>
-          {!isProgressing && canEditMilestone && (
+          {!isUndergoing && canEditMilestone && (
             <>
               <button className="btn-primary" onClick={() => { setActiveTab('tasks'); setShowCreateTask(true) }}>+ Create Task</button>
               <button className="btn-primary" onClick={() => { setActiveTab('supports'); setShowCreateSupport(true) }}>+ Create Support</button>
               <button className="btn-primary" onClick={() => { setActiveTab('meetings'); setShowCreateMeeting(true) }}>+ Schedule Meeting</button>
             </>
           )}
-          {isProgressing && <span className="text-dim">Milestone is in progress - cannot add new items</span>}
+          {isUndergoing && <span className="text-dim">Milestone is undergoing - cannot add new items</span>}
         </div>
 
         <MilestoneFormModal

src/pages/MilestonesPage.tsx

@@ -51,7 +51,7 @@ export default function MilestonesPage() {
         {milestones.map((ms) => (
           <div key={ms.id} className="milestone-card" onClick={() => navigate(`/milestones/${ms.id}`)}>
             <div className="milestone-card-header">
-              <span className={`badge status-${ms.status === 'progressing' ? 'in_progress' : ms.status}`}>{ms.status}</span>
+              <span className={`badge status-${ms.status}`}>{ms.status}</span>
               <h3>{ms.title}</h3>
             </div>
             <p className="project-desc">{ms.description || 'No description'}</p>

src/pages/TaskDetailPage.tsx

@@ -63,9 +63,10 @@ export default function TaskDetailPage() {
   if (!task) return <div className="loading">Loading...</div>
 
   const statusActions: Record<string, string[]> = {
-    open: ['progressing', 'closed'],
-    pending: ['progressing', 'closed'],
-    progressing: ['pending', 'closed'],
+    open: ['undergoing', 'closed'],
+    pending: ['open', 'closed'],
+    undergoing: ['completed', 'closed'],
+    completed: ['open'],
     closed: ['open'],
   }
 

src/types/index.ts

@@ -35,7 +35,7 @@ export interface Task {
   description: string | null
   task_type: 'issue' | 'maintenance' | 'research' | 'review' | 'story' | 'test' | 'resolution' | 'task'
   task_subtype: string | null
-  status: 'open' | 'pending' | 'progressing' | 'closed'
+  status: 'open' | 'pending' | 'undergoing' | 'completed' | 'closed'
   priority: 'low' | 'medium' | 'high' | 'critical'
   project_id: number
   milestone_id: number | null
@@ -64,7 +64,8 @@ export interface Milestone {
   id: number
   title: string
   description: string | null
-  status: 'open' | 'pending' | 'deferred' | 'progressing' | 'closed'
+  status: 'open' | 'freeze' | 'undergoing' | 'completed' | 'closed'
+  started_at: string | null
   project_id: number
   created_by_id: number | null
   due_date: string | null