feat: add about, contact with map, legal pages and 404

- About page with identity cards and equipment lists (about.json)
- Contact page: station info, obfuscated e-mail, lazy Leaflet/OSM map
  with antenna tower marker and dark-mode tiles
- Privacy, license and disclaimer pages from a legal collection
- QRT-themed 404 page
- LICENSE (MIT) and LICENSE-CONTENT (CC BY-SA 4.0 legal code)
- Shared PageHeader and CodeCopy components

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

package-lock.json

@@ -19,11 +19,13 @@
         "@tailwindcss/vite": "^4.3.3",
         "astro": "^7.4.0",
         "astro-icon": "^1.2.0",
+        "leaflet": "^1.9.4",
         "tailwindcss": "^4.3.3"
       },
       "devDependencies": {
         "@astrojs/check": "^0.9.10",
         "@tailwindcss/typography": "^0.5.20",
+        "@types/leaflet": "^1.9.22",
         "pagefind": "^1.5.2",
         "prettier": "^3.9.10",
         "prettier-plugin-astro": "^1.1.1",
@@ -2603,6 +2605,13 @@
         "@types/estree": "*"
       }
     },
+    "node_modules/@types/geojson": {
+      "version": "7946.0.16",
+      "resolved": "https://registry.npmjs.org/@types/geojson/-/geojson-7946.0.16.tgz",
+      "integrity": "sha512-6C8nqWur3j98U6+lXDfTUWIfgvZU+EumvpHKcYjujKH7woYyLj2sUmff0tRhrqM7BohUw7Pz3ZB1jj2gW9Fvmg==",
+      "dev": true,
+      "license": "MIT"
+    },
     "node_modules/@types/hast": {
       "version": "3.0.5",
       "resolved": "https://registry.npmjs.org/@types/hast/-/hast-3.0.5.tgz",
@@ -2612,6 +2621,16 @@
         "@types/unist": "*"
       }
     },
+    "node_modules/@types/leaflet": {
+      "version": "1.9.22",
+      "resolved": "https://registry.npmjs.org/@types/leaflet/-/leaflet-1.9.22.tgz",
+      "integrity": "sha512-h3lhECYEKDasG7LFHu+GiHqAvsgLuQvlJvVZzJDGONo3sEL+wUOqSFLnwkZlK0qVxnxbuGFW8iBlJNYs5wgndA==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "@types/geojson": "*"
+      }
+    },
     "node_modules/@types/mdast": {
       "version": "4.0.4",
       "resolved": "https://registry.npmjs.org/@types/mdast/-/mdast-4.0.4.tgz",
@@ -3932,6 +3951,12 @@
         "node": ">=6"
       }
     },
+    "node_modules/leaflet": {
+      "version": "1.9.4",
+      "resolved": "https://registry.npmjs.org/leaflet/-/leaflet-1.9.4.tgz",
+      "integrity": "sha512-nxS1ynzJOmOlHp+iL3FyWqK89GtNL8U8rvlMOsQdTTssxZwCXh8N2NB3GDQOL+YR3XnWyZAxwQixURb+FA74PA==",
+      "license": "BSD-2-Clause"
+    },
     "node_modules/lightningcss": {
       "version": "1.33.0",
       "resolved": "https://registry.npmjs.org/lightningcss/-/lightningcss-1.33.0.tgz",