feat(i18n): translate expert-modal SelectItems + billing-toggle aria-labels #19

Severity

P1 — i18n coverage

Context

PR-7 in the audit plan covered `marketing/pricing/sections/*` and `marketing/expert-modal.tsx` as i18n gaps. Investigation showed:

• `pricing/sections/{hero-landing,testimonials,features,pricing-faq}.tsx` are dead code — no caller references them. They're SaaS-Starter clone artifacts. The live pricing page renders `pricing-header.tsx`, `pricing-cards.tsx`, `compare-plans.tsx`, `pricing-faqs.tsx`, `enterprise-section.tsx` — all of which are already fully i18n'd.
• `pricing-faq.tsx` is imported but commented out in `content.tsx` line 32.
• `pricing/billing-info.tsx` and `pricing/forms/user-role-form.tsx` have Class 1 dead imports (separate issue).
• `pricing/forms/newsletter-form.tsx` is unused.

So the realistic scope shrinks to two live components:

1. `marketing/expert-modal.tsx` — Select items hardcoded (project types, budgets, timelines)
2. `marketing/pricing/billing-toggle.tsx` — aria-labels hardcoded

Changes

• Add to `expert.*`: `projectTypes.{website,ecommerce,mobile,custom,consulting}`, `budgets.{lt1000,1000to5000,5000to10000,gt10000}`, `timelines.{asap,oneMonth,oneToThreeMonths,threeToSixMonths}`, `toggleMonthlyAria`, `toggleYearlyAria` — Arabic translations for all
• `expert-modal.tsx` — wire SelectItem children to dict keys
• `billing-toggle.tsx` — wire aria-labels to dict keys

Acceptance criteria

• /ar pricing page → toggle reads `تبديل الفوترة الشهرية` / `تبديل الفوترة السنوية` for screen readers
• Expert modal in /ar shows Arabic dropdown options for project type, budget, timeline
• /en unchanged visually
• No new TS errors

Out of scope (separate PRs)

• Pricing dead-code cleanup — needs decision: delete `sections/*` and `pricing-faq.tsx` and `newsletter-form.tsx`?
• Class 1 dead imports in `billing-info.tsx` and `user-role-form.tsx`

Reference

Plan: PR-7 (scope revised to live components only).