feat(ui) : add create task button on my-tasks and responsive kanban columns

- Add "Créer une tâche" button on my-tasks page with mandatory project selector
- TaskModal now accepts optional projects prop for project selection in create mode
- Replace fixed-width kanban columns (w-72 shrink-0) with flexible layout (min-w-36 flex-1)
- Add min-w-0 and overflow-x-hidden on default layout to properly contain content
- Kanban now adapts to screen size from 1024px to 1920px+

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

frontend/components/task/TaskModal.vue

@@ -65,6 +65,20 @@
                             @blur="touched.title = true"
                         />
 
+                        <!-- Project select (create mode with project list) -->
+                        <div v-if="showProjectSelect" class="mt-4">
+                            <MalioSelect
+                                v-model="form.projectId"
+                                :options="projectOptions"
+                                label="Projet *"
+                                empty-option-label="Sélectionner un projet"
+                                min-width="w-full"
+                            />
+                            <p v-if="touched.project && !form.projectId" class="mt-1 text-xs text-red-500">
+                                Le projet est requis
+                            </p>
+                        </div>
+
                         <!-- Two-column selects -->
                         <div class="mt-4 grid grid-cols-1 gap-x-6 gap-y-4 sm:grid-cols-2">
                             <MalioSelect
@@ -266,6 +280,8 @@ import type { TaskGroup } from '~/services/dto/task-group'
 import type { UserData } from '~/services/dto/user-data'
 import { useTaskService } from '~/services/tasks'
 
+import type { Project } from '~/services/dto/project'
+
 const props = defineProps<{
     modelValue: boolean
     task: Task | null
@@ -276,6 +292,7 @@ const props = defineProps<{
     tags: TaskTag[]
     groups: TaskGroup[]
     users: UserData[]
+    projects?: Project[]
 }>()
 
 const emit = defineEmits<{
@@ -318,10 +335,12 @@ const form = reactive({
     groupId: null as number | null,
     tagIds: [] as number[],
     clientTicketId: null as number | null,
+    projectId: null as number | null,
 })
 
 const touched = reactive({
     title: false,
+    project: false,
 })
 
 const statusOptions = computed(() =>
@@ -340,8 +359,22 @@ const userOptions = computed(() =>
     props.users.map(u => ({ label: u.username, value: u.id }))
 )
 
-const groupOptions = computed(() =>
-    props.groups.map(g => ({ label: g.title, value: g.id }))
+const groupOptions = computed(() => {
+    let filtered = props.groups
+    if (showProjectSelect.value && form.projectId) {
+        filtered = filtered.filter(g => g.project?.id === form.projectId)
+    }
+    return filtered.map(g => ({ label: g.title, value: g.id }))
+})
+
+const showProjectSelect = computed(() => !!props.projects?.length && !isEditing.value)
+
+const projectOptions = computed(() =>
+    (props.projects ?? []).map(p => ({ label: p.name, value: p.id }))
+)
+
+const resolvedProjectId = computed(() =>
+    showProjectSelect.value ? form.projectId : props.projectId
 )
 
 const canArchive = computed(() => {
@@ -385,8 +418,10 @@ function populateForm(task: Task | null) {
         form.groupId = null
         form.tagIds = []
         form.clientTicketId = null
+        form.projectId = null
     }
     touched.title = false
+    touched.project = false
 }
 
 watch(() => props.modelValue, async (open) => {
@@ -394,9 +429,14 @@ watch(() => props.modelValue, async (open) => {
         confirmDeleteDocOpen.value = false
         documentToDelete.value = null
         populateForm(props.task)
-        try {
-            clientTickets.value = await clientTicketService.getAll({ project: props.projectId })
-        } catch {
+        const pid = resolvedProjectId.value
+        if (pid) {
+            try {
+                clientTickets.value = await clientTicketService.getAll({ project: pid })
+            } catch {
+                clientTickets.value = []
+            }
+        } else {
             clientTickets.value = []
         }
         if (props.task?.project?.giteaOwner && props.task?.project?.giteaRepo && !giteaUrl.value) {
@@ -426,6 +466,22 @@ const clientTicketOptions = computed(() =>
     clientTickets.value.map(ct => ({ label: `CT-${String(ct.number).padStart(3, '0')} — ${ct.title}`, value: ct.id }))
 )
 
+// Reset group and reload client tickets when project changes in create mode
+watch(() => form.projectId, async (pid) => {
+    if (!showProjectSelect.value) return
+    form.groupId = null
+    form.clientTicketId = null
+    if (pid) {
+        try {
+            clientTickets.value = await clientTicketService.getAll({ project: pid })
+        } catch {
+            clientTickets.value = []
+        }
+    } else {
+        clientTickets.value = []
+    }
+})
+
 const authStore = useAuthStore()
 const isAdmin = computed(() => authStore.user?.roles?.includes('ROLE_ADMIN') ?? false)
 
@@ -541,7 +597,9 @@ async function handleUnarchive() {
 
 async function handleSubmit() {
     touched.title = true
+    touched.project = true
     if (!form.title.trim()) return
+    if (showProjectSelect.value && !form.projectId) return
 
     isSubmitting.value = true
     try {
@@ -553,7 +611,7 @@ async function handleSubmit() {
             priority: form.priorityId ? `/api/task_priorities/${form.priorityId}` : null,
             assignee: form.assigneeId ? `/api/users/${form.assigneeId}` : null,
             group: form.groupId ? `/api/task_groups/${form.groupId}` : null,
-            project: `/api/projects/${props.projectId}`,
+            project: `/api/projects/${resolvedProjectId.value}`,
             tags: form.tagIds.map(id => `/api/task_tags/${id}`),
             clientTicket: form.clientTicketId ? `/api/client_tickets/${form.clientTicketId}` : null,
         }