feat: add inline lead form to homepage

Mounts a 3-field lead-capture form (name, email-or-phone, project type)
between the FAQ/tech-stack block and the final CTA band so visitors who
are ready to start a project can submit without leaving the homepage.
Cuts the friction step of routing every CTA through /contact.

- New src/components/InlineLeadForm.astro:
  * Heading, micro-trust subhead, honeypot, client-side validation
  * Smart contact-field routing: detects email vs phone and synthesises
    a placeholder email for phone-only leads so the existing /api/contact
    validator accepts them (the real phone is preserved and surfaced in
    the admin notification)
  * In-place success state with phone + WhatsApp fallbacks; no navigation
  * 48px touch targets, dark-mode safe, autocomplete + inputmode attrs
- src/pages/api/contact.ts: accept and surface `source` / `projectType`
  metadata (allowlisted source values, free-text projectType capped at
  80 chars), add `erp-solutions` and `government-systems` subject codes,
  and include the source/project info in both the admin email and logs.
- src/pages/index.astro: import + mount InlineLeadForm above the final
  CTA section.
- tests/inline-lead-form.spec.ts: 8 specs covering UI render, mobile
  attributes, blank-field validation, email-submit + phone-submit
  payload routing, and server-side acceptance of the new payload shape,
  new subjects, and unknown-source fallback.

src/pages/index.astro

@@ -3,6 +3,7 @@
 import BaseLayout from '../layouts/BaseLayout.astro';
 import SEO from '../components/SEO.astro';
 import ClientLogos from '../components/ClientLogos.astro';
+import InlineLeadForm from '../components/InlineLeadForm.astro';
 
 // Benefits/Features data
 const benefits = [
@@ -708,6 +709,13 @@ const faqs = [
     </div>
   </section>
 
+  <!-- Inline Lead Form — sits between the FAQ/tech-stack social-proof block
+       and the final CTA band so visitors who are ready to start a project can
+       submit a 3-field enquiry without leaving the homepage. Submits to the
+       same /api/contact endpoint and is tagged `source: 'homepage-inline'` so
+       the lead can be segmented downstream. -->
+  <InlineLeadForm />
+
   <!-- Final CTA Section - Enhanced -->
   <section class="py-24 bg-gradient-to-br from-secondary-900 via-primary-900 to-primary-800 relative overflow-hidden">
     <!-- Background decorations -->