feat(activities): stationary Filters column next to scrolling pills

Filters icon + Clear-all sit in a stationary left-aligned column;
only the All/Today/Tomorrow/etc temporal pills scroll horizontally.
Clear-all is tucked tightly under the Filters icon (h-5, 10px text,
gap-0.5) and shows only when a filter is active. The badge no
longer lives inside the overflow-x scroll container, so the count
chip isn't clipped at the corner anymore.

src/modules/activities/views/ActivitiesPage.vue

@@ -9,7 +9,7 @@ import {
   CollapsibleTrigger,
 } from '@/components/ui/collapsible'
 import { Separator } from '@/components/ui/separator'
-import { SlidersHorizontal, ChevronDown, History } from 'lucide-vue-next'
+import { SlidersHorizontal, History } from 'lucide-vue-next'
 import { useActivities } from '../composables/useActivities'
 import ActivitySearchOverlay from '../components/ActivitySearchOverlay.vue'
 import TemporalFilterBar from '../components/TemporalFilterBar.vue'
@@ -77,45 +77,47 @@ function handleSelectActivity(activity: Activity) {
       <DatePickerStrip :selected-date="selectedDate" @select="selectDate" />
     </div>
 
-    <!-- Temporal filter pills -->
+    <!-- Filters trigger + Clear-all stay stationary in a left-aligned
-    <div class="mb-3">
+         column; only the temporal pills scroll horizontally. The
-      <TemporalFilterBar :model-value="temporal" @update:model-value="setTemporal" />
+         Filters icon (with a count badge when past-events or any
-    </div>
+         categories are active) opens a collapsible that hosts the
-
+         past-events toggle + category chips below. -->
-    <!-- Filters collapsible (categories + past-events). Past events used
+    <Collapsible v-model:open="filtersOpen" class="mb-3">
-         to live on its own row above the trigger; folded in here so the
+      <div class="flex items-start gap-3">
-         feed gets that vertical real estate by default. The Clear-all
+        <div class="shrink-0 flex flex-col items-center gap-0.5">
-         affordance shares the trigger row when any filter is active so
-         the old "Filters active" notice doesn't claim another row. -->
-    <Collapsible v-model:open="filtersOpen" class="mb-4">
-      <div class="flex items-center gap-1">
           <CollapsibleTrigger as-child>
-          <Button variant="ghost" size="sm" class="gap-1.5 px-2 text-muted-foreground">
+            <Button
+              variant="ghost"
+              size="icon"
+              class="rounded-full h-8 w-8 relative"
+              :class="{ 'bg-accent text-accent-foreground': filtersOpen || filterCount > 0 }"
+              :aria-label="t('activities.filters.filters', 'Filters')"
+              :aria-expanded="filtersOpen"
+            >
               <SlidersHorizontal class="w-4 h-4" />
-            {{ t('activities.filters.filters', 'Filters') }}
               <span
                 v-if="filterCount > 0"
-              class="text-xs bg-primary text-primary-foreground rounded-full px-1.5"
+                class="absolute -top-1 -right-1 min-w-[16px] h-[16px] px-1 rounded-full bg-primary text-primary-foreground text-[10px] font-semibold flex items-center justify-center"
               >
                 {{ filterCount }}
               </span>
-            <ChevronDown
-              class="w-3.5 h-3.5 transition-transform"
-              :class="{ 'rotate-180': filtersOpen }"
-            />
             </Button>
           </CollapsibleTrigger>
           <Button
             v-if="hasActiveFilters"
             variant="ghost"
             size="sm"
-          class="h-7 px-2 text-xs text-muted-foreground"
+            class="h-5 px-1 text-[10px] text-muted-foreground"
             @click="resetFilters"
           >
             {{ t('activities.filters.clearAll', 'Clear all') }}
           </Button>
         </div>
-      <CollapsibleContent class="mt-2 space-y-3">
+        <div class="flex-1 min-w-0 pt-0.5">
+          <TemporalFilterBar :model-value="temporal" @update:model-value="setTemporal" />
+        </div>
+      </div>
+      <CollapsibleContent class="mt-3 space-y-3">
         <Button
           :variant="showPast ? 'default' : 'outline'"
           size="sm"