Replace freetext email inputs with a user lookup for tag/assign/reallocate

Typo'd addresses in the old <input type="email"> fields silently matched
nobody (assigned_to/task_tags.user_email have no FK), so a task could vanish
into an unreachable owner with no error. New UsersContext + UserPicker pull
the real user list from central auth (/api/auth/users?app=tasks), same
pattern maintenance already uses for its assignee dropdown.

frontend/src/App.tsx

@@ -8,6 +8,7 @@ import { ListsProvider } from './context/ListsContext'
 import { StatusesProvider } from './context/StatusesContext'
 import { CategoriesProvider } from './context/CategoriesContext'
 import { ProjectsProvider } from './context/ProjectsContext'
+import { UsersProvider } from './context/UsersContext'
 import { SearchProvider } from './context/SearchContext'
 import { TaskFiltersProvider } from './context/TaskFiltersContext'
 import { TaskDrawerProvider } from './components/TaskDrawer'
@@ -30,6 +31,7 @@ export default function App() {
             <StatusesProvider>
               <CategoriesProvider>
                 <ProjectsProvider>
+                  <UsersProvider>
                     <SearchProvider>
                       <TaskFiltersProvider>
                         <TaskDrawerProvider>
@@ -51,6 +53,7 @@ export default function App() {
                         </TaskDrawerProvider>
                       </TaskFiltersProvider>
                     </SearchProvider>
+                  </UsersProvider>
                 </ProjectsProvider>
               </CategoriesProvider>
             </StatusesProvider>

frontend/src/api.ts

@@ -1,4 +1,4 @@
-import type { List, Task, TaskDetail, TaskItem, TaskComment, AppConfig, AppStatus, Category, Project, ProjectDetail } from './types'
+import type { List, Task, TaskDetail, TaskItem, TaskComment, AppConfig, AppStatus, Category, Project, ProjectDetail, AuthUser } from './types'
 
 const BASE = '/tasks/api'
 
@@ -137,6 +137,11 @@ export function addComment(taskId: number, body: string): Promise<TaskComment> {
   return request(`/tasks/${taskId}/comments`, { method: 'POST', body: JSON.stringify({ body }) })
 }
 
+// ── Users (for tag/assign/reallocate pickers) ───────────────────
+export function fetchAssignableUsers(): Promise<AuthUser[]> {
+  return request('/auth/users?app=tasks')
+}
+
 // ── Config ───────────────────────────────────────────────────
 export function fetchConfig(): Promise<AppConfig> {
   return request('/config')

frontend/src/components/TaskDetail.tsx

@@ -13,7 +13,7 @@ import { useProjects } from '../context/ProjectsContext'
 import { useStatuses } from '../context/StatusesContext'
 import { useAuth } from './AuthGate'
 import { can } from '../types'
-import { Check_, formatDateTime, toLocalInput } from './shared'
+import { Check_, formatDateTime, toLocalInput, UserPicker } from './shared'
 
 export default function TaskDetail({ taskId, onChange, onClose }:
   { taskId: number; onChange: () => void; onClose: () => void }) {
@@ -226,24 +226,16 @@ export default function TaskDetail({ taskId, onChange, onClose }:
             </div>
           )}
           {isOwner && (
-            <div style={{ display: 'flex', gap: 6 }}>
-              <input type="email" value={tagEmail} placeholder="colleague@hotel.com"
-                onChange={e => setTagEmail(e.target.value)}
-                onKeyDown={e => { if (e.key === 'Enter') addTag() }} />
-              <button className="btn btn-sm" onClick={addTag} disabled={!tagEmail.trim()}>Tag</button>
-            </div>
+            <UserPicker value={tagEmail} onChange={setTagEmail} onSubmit={addTag} buttonLabel="Tag"
+              exclude={[user.email, ...task.tags.map(tg => tg.user_email)]} />
           )}
         </div>
 
         {isOwner && can(user, 'assign') && (
           <div className="field" style={{ marginBottom: can(user, 'reallocate') ? 8 : 0 }}>
             <label><UserPlus size={12} strokeWidth={1.75} style={{ verticalAlign: -1 }} /> Assign (hands off ownership)</label>
-            <div style={{ display: 'flex', gap: 6 }}>
-              <input type="email" value={assignEmail} placeholder={task.assigned_to ?? 'someone@hotel.com'}
-                onChange={e => setAssignEmail(e.target.value)}
-                onKeyDown={e => { if (e.key === 'Enter') assignTo() }} />
-              <button className="btn btn-sm" onClick={assignTo} disabled={!assignEmail.trim()}>Assign</button>
-            </div>
+            <UserPicker value={assignEmail} onChange={setAssignEmail} onSubmit={assignTo} buttonLabel="Assign"
+              exclude={[user.email]} />
             {task.assigned_to && <div className="field-hint">Currently assigned to {task.assigned_to}</div>}
           </div>
         )}
@@ -251,12 +243,7 @@ export default function TaskDetail({ taskId, onChange, onClose }:
         {can(user, 'reallocate') && (
           <div className="field" style={{ marginBottom: 0 }}>
             <label><Send size={12} strokeWidth={1.75} style={{ verticalAlign: -1 }} /> Reallocate (dispatcher — moves to anyone)</label>
-            <div style={{ display: 'flex', gap: 6 }}>
-              <input type="email" value={reallocateEmail} placeholder="someone@hotel.com"
-                onChange={e => setReallocateEmail(e.target.value)}
-                onKeyDown={e => { if (e.key === 'Enter') reallocateTo() }} />
-              <button className="btn btn-sm" onClick={reallocateTo} disabled={!reallocateEmail.trim()}>Move</button>
-            </div>
+            <UserPicker value={reallocateEmail} onChange={setReallocateEmail} onSubmit={reallocateTo} buttonLabel="Move" />
           </div>
         )}
 

frontend/src/components/shared.tsx

@@ -6,6 +6,7 @@ import { useCategories } from '../context/CategoriesContext'
 import { useProjects } from '../context/ProjectsContext'
 import { useLists } from '../context/ListsContext'
 import { useTaskFilters } from '../context/TaskFiltersContext'
+import { useUsers } from '../context/UsersContext'
 
 export function PriorityBadge({ priority }: { priority: Priority }) {
   if (priority === 'medium') return null
@@ -22,6 +23,30 @@ export function Check_({ isDone, onClick }: { isDone: boolean; onClick: (e: Reac
   )
 }
 
+// User lookup + submit button, replacing a freetext email input wherever a
+// task gets tagged/assigned/reallocated — avoids typo'd addresses silently
+// matching nobody (assigned_to/task_tags.user_email have no FK to users).
+export function UserPicker({ value, onChange, onSubmit, exclude = [], placeholder = 'Choose a person…', buttonLabel }: {
+  value: string
+  onChange: (email: string) => void
+  onSubmit: () => void
+  exclude?: string[]
+  placeholder?: string
+  buttonLabel: string
+}) {
+  const { users } = useUsers()
+  const options = users.filter(u => !exclude.includes(u.email))
+  return (
+    <div style={{ display: 'flex', gap: 6 }}>
+      <select value={value} onChange={e => onChange(e.target.value)}>
+        <option value="">{placeholder}</option>
+        {options.map(u => <option key={u.email} value={u.email}>{u.name} ({u.email})</option>)}
+      </select>
+      <button className="btn btn-sm" onClick={onSubmit} disabled={!value}>{buttonLabel}</button>
+    </div>
+  )
+}
+
 interface FilterableEntity { id: number; name: string; colour: string }
 
 // Collapsible multi-select filter chip-bar — generic over anything with an

frontend/src/context/UsersContext.tsx

@@ -0,0 +1,32 @@
+import { createContext, useContext, useEffect, useState, useCallback } from 'react'
+import type { AuthUser } from '../types'
+import { fetchAssignableUsers } from '../api'
+
+interface UsersCtx {
+  users: AuthUser[]
+  loading: boolean
+  reload: () => Promise<void>
+}
+
+const Ctx = createContext<UsersCtx | null>(null)
+
+export function useUsers() {
+  const ctx = useContext(Ctx)
+  if (!ctx) throw new Error('useUsers must be used inside UsersProvider')
+  return ctx
+}
+
+export function UsersProvider({ children }: { children: React.ReactNode }) {
+  const [users, setUsers] = useState<AuthUser[]>([])
+  const [loading, setLoading] = useState(true)
+
+  const reload = useCallback(async () => {
+    const data = await fetchAssignableUsers().catch(() => [])
+    setUsers(data)
+    setLoading(false)
+  }, [])
+
+  useEffect(() => { reload() }, [reload])
+
+  return <Ctx.Provider value={{ users, loading, reload }}>{children}</Ctx.Provider>
+}

frontend/src/pages/DispatchView.tsx

@@ -6,7 +6,7 @@ import { useAuth } from '../components/AuthGate'
 import { useSearch } from '../context/SearchContext'
 import { useTaskFilters } from '../context/TaskFiltersContext'
 import { can } from '../types'
-import { dueInfo, PriorityBadge, TaskFilterBar } from '../components/shared'
+import { dueInfo, PriorityBadge, TaskFilterBar, UserPicker } from '../components/shared'
 
 // A flat, cross-user list for the 'reallocate' cap — deliberately not routed
 // through the shared task drawer, since GET /api/tasks/:id only grants
@@ -83,10 +83,8 @@ export default function DispatchView() {
             </div>
             {movingId === t.id ? (
               <div style={{ display: 'flex', gap: 6 }}>
-                <input type="email" autoFocus value={target} placeholder="reallocate to…" style={{ width: 180 }}
-                  onChange={e => setTarget(e.target.value)}
-                  onKeyDown={e => { if (e.key === 'Enter') move(t.id); if (e.key === 'Escape') setMovingId(null) }} />
-                <button className="btn btn-sm btn-primary" onClick={() => move(t.id)} disabled={!target.trim()}>Move</button>
+                <UserPicker value={target} onChange={setTarget} onSubmit={() => move(t.id)} buttonLabel="Move"
+                  exclude={[t.owner_id]} placeholder="reallocate to…" />
                 <button className="btn btn-sm" onClick={() => setMovingId(null)}>Cancel</button>
               </div>
             ) : (

frontend/src/types.ts

@@ -141,6 +141,13 @@ export interface User {
   caps: string[]   // bare slugs — verify?app=tasks strips the prefix
 }
 
+// Users with access to this app, served by the central auth service.
+export interface AuthUser {
+  id: number
+  email: string
+  name: string
+}
+
 export function can(user: User, cap: string): boolean {
   return user.is_admin || user.caps.includes(cap)
 }