feat(project-management) : extract Projects/Tasks front into Nuxt module layer

Tranche 4 of LST-65. Companion to the backend module migration.

- Move pages (my-tasks, projects, projects/[id]/{index,groups,archives}),
  18 components (project + task), 10 services and 10 DTOs into
  frontend/modules/project-management/ (auto-detected layer).
- Rewrite explicit ~/services/* and ~/services/dto/* imports across 38
  consumers (admin tabs, mail modals, dashboard, mail page, layout) including
  the time-tracking module whose DTOs referenced project/task/task-tag.
- clients.ts and shared DTOs (client, user-data) stay at the root.
- Routes /my-tasks, /projects, /projects/:id(/groups|/archives) preserved;
  i18n stays global.

nuxt build passes; routes confirmed.

frontend/modules/project-management/components/StatusPickerPopover.vue

@@ -0,0 +1,35 @@
+<script setup lang="ts">
+import type { TaskStatus } from '~/modules/project-management/services/dto/task-status'
+
+defineProps<{
+    statuses: TaskStatus[]
+    x: number
+    y: number
+}>()
+
+const emit = defineEmits<{
+    pick: [status: TaskStatus]
+    cancel: []
+}>()
+</script>
+
+<template>
+    <Teleport to="body">
+        <div class="fixed inset-0 z-[60]" @click="emit('cancel')" />
+        <div
+            class="fixed z-[61] min-w-44 rounded-lg border border-neutral-200 bg-white py-1 shadow-xl"
+            :style="{ left: x + 'px', top: y + 'px' }"
+        >
+            <button
+                v-for="s in statuses"
+                :key="s.id"
+                type="button"
+                class="flex w-full items-center gap-2 px-3 py-2 text-left text-sm hover:bg-neutral-50"
+                @click="emit('pick', s)"
+            >
+                <span class="h-3 w-3 shrink-0 rounded-full" :style="{ backgroundColor: s.color }" />
+                {{ s.label }}
+            </button>
+        </div>
+    </Teleport>
+</template>