Give the tech radar its own page

/radar (/en/radar, /ca/radar) shows every technology the collective has
placed, by ring: logo, category, what it is, why it sits there, its
website and how many projects use it. The landing's radar summary links
to it.

It is the first listing — a page this site composes rather than one
record's — so resolveRoute learns about those (LISTINGS), and builds
their addresses and hreflang alternates from the same table.

Logos sit on a light tile in both themes. A brand's mark is not ours to
recolour, and Rust's, which is black, would vanish in dark mode.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

landing/src/app/pages/home.page.scss

@@ -73,3 +73,18 @@
     border-radius: 0.5rem;
   }
 }
+
+// "See the full radar" under the section's summary of it.
+.landing-section__more {
+  margin: 2rem 0 0;
+
+  a {
+    color: var(--pi-color-primary);
+    font-weight: 600;
+    text-decoration: none;
+
+    &:hover {
+      text-decoration: underline;
+    }
+  }
+}