feat: comprehensive UI overhaul + budget allocation redesign

Audit & Quality:
- RTL: replaced 121 LTR-only utilities (text-left, pl-, left-) with logical properties
- A11y: focus traps + ARIA on Modal/SlidePanel/TabbedModal, clickable divs→buttons
- Theming: bg-white→bg-surface (170 instances), text-gray→semantic tokens
- Performance: useMemo on filters, loading="lazy" on 24 images
- CSS: prefers-reduced-motion, removed dead animations

Component Splits:
- PostDetailPanel: 1332→623 lines + 4 sub-components
- ArtefactDetailPanel: 972→590 lines + 1 sub-component

Brand Identity — Rawaj (رواج):
- New name, DM Sans font, deep teal palette (#0d9488)
- Custom SVG logo, forest-tinted dark mode
- All emails branded with app name in subject line

Design Refinement:
- Dashboard: merged posts+deadlines into tabbed ActivityFeed, inline stats
- Quieter: removed card lift, brand glow, gradient text, mesh backgrounds
- CampaignDetail: prominent budget card, compact team avatars, Lucide icons
- Consistent page titles via Header.jsx, standardized section headers
- Finance page fully i18n'd (20+ hardcoded strings replaced)

Budget Allocation Redesign:
- Single source of truth: BudgetEntries (Campaign.budget deprecated)
- Validation at all levels: main→campaign→track, expenses blocked if insufficient
- Budget request workflow with CEO approval via public link
- BudgetRequests table, CRUD routes, public approval page
- Budget mutex for race condition prevention
- Idempotent migration for existing campaign budgets

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

client/src/components/ArtefactVersionTimeline.jsx

@@ -85,6 +85,7 @@ export default function ArtefactVersionTimeline({ versions, activeVersionId, onS
                   src={version.thumbnail}
                   alt={`Version ${version.version_number}`}
                   className="w-full h-20 object-cover rounded border border-border"
+                  loading="lazy"
                 />
               </div>
             )}