- Add "Explore our other services" block to service landing pages

with colour-tinted cards + Our Pricing entry (grey "All services" pill)
- Wrap homepage Instagram CTA in <aside aria-label="...">
- Always emit og:image:width/height with 1200x630 fallback when
  image metadata is unknown
- Add aria-current="page" to active desktop, mega-menu, and mobile
  nav links (exact-path match only — not "Services" parent)
- Richer testimonial alt text derived from dog name in the detail
  field (e.g. "Archie, a happy Goodwalk dog walking client...")
- Tier sitemap.xml priorities: home 1.0, services 0.9, pricing 0.8,
  about/contact 0.7, legal 0.3 (yearly changefreq)
- Bump to 4.1.0

src/lib/components/SeoHead.svelte

@@ -65,10 +65,8 @@
   <meta property="og:image" content={imageUrl} />
   <meta property="og:image:secure_url" content={imageUrl} />
   <meta property="og:image:alt" content={imageAlt} />
-  {#if imageMeta}
-    <meta property="og:image:width" content={String(imageMeta.width)} />
-    <meta property="og:image:height" content={String(imageMeta.height)} />
-  {/if}
+  <meta property="og:image:width" content={String(imageMeta?.width ?? 1200)} />
+  <meta property="og:image:height" content={String(imageMeta?.height ?? 630)} />
 
   <meta name="twitter:card" content="summary_large_image" />
   <meta name="twitter:site" content="@goodwalk.nz" />