feat: implement Story 2.4 — Dashboard Activity Feed with review fixes

Add role-scoped activity feed to the dashboard showing the 20 most recent
workspace events. Owners/Managers see all activity (declarations, clients,
team changes); Workers see only their assigned declarations. Includes
French descriptions, relative timestamps, responsive layout (desktop
sidebar, tablet inline, mobile collapsible), and 7 passing Pest tests.

Review fixes applied: batch-load declarations/clients/users to eliminate
N+1 queries, consistent soft-delete handling in URL resolution, French
grammar singular/plural fix, missing icon map entry, and corrected tablet
breakpoint per spec.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

tests/Pest.php

@@ -13,6 +13,9 @@
 
 pest()->extend(Tests\TestCase::class)
     ->use(Illuminate\Foundation\Testing\RefreshDatabase::class)
+    ->beforeEach(function () {
+        $this->withoutVite();
+    })
     ->in('Feature');
 
 /*