feat: add SSR and prerendering support

- Install @angular/ssr and @angular/platform-server (v21.2.x)
- Create server entry point (server.ts) and server bootstrap (main.server.ts)
- Add server routes config (app.server.routes.ts) with 5 prerendered routes:
  /, /about, /schedule, /events, /contact
- Update angular.json with server/ssr/prerender build configuration
- Add prerender-routes.txt for build-time static route generation
- Fix SSR compatibility:
  - App component: guard DOM access with isPlatformBrowser
  - StructuredDataComponent: skip head manipulation on server
  - ThemeService: skip CSS variable application on server
  - ShowService/EventService: return empty arrays on API failure
    (graceful fallback during prerender with no backend)
- Prerendered output verified: 5 static HTML routes in dist/

package-lock.json

@@ -14,7 +14,9 @@
         "@angular/core": "^21.2.0",
         "@angular/forms": "^21.2.0",
         "@angular/platform-browser": "^21.2.0",
+        "@angular/platform-server": "^21.2.19",
         "@angular/router": "^21.2.0",
+        "@angular/ssr": "^21.2.20",
         "@types/leaflet": "^1.9.17",
         "chart.js": "^4.4.0",
         "leaflet": "^1.9.4",
@@ -29,6 +31,7 @@
         "@angular/cli": "^21.2.14",
         "@angular/compiler-cli": "^21.2.0",
         "@types/jsdom": "^21.1.7",
+        "@types/node": "^26.1.2",
         "@vitest/coverage-v8": "^4.0.8",
         "jsdom": "^26.1.0",
         "prettier": "^3.8.1",
@@ -603,6 +606,26 @@
         }
       }
     },
+    "node_modules/@angular/platform-server": {
+      "version": "21.2.19",
+      "resolved": "https://registry.npmjs.org/@angular/platform-server/-/platform-server-21.2.19.tgz",
+      "integrity": "sha512-UVyUIj04LRBoi4KfvxeZYPohzh80nSqamxpb8uzsYFKVSYdZSHDiFaE6OOzj0YST1rs2/LC92cPE2TY7IQIdew==",
+      "license": "MIT",
+      "dependencies": {
+        "tslib": "^2.3.0",
+        "xhr2": "^0.2.0"
+      },
+      "engines": {
+        "node": "^20.19.0 || ^22.12.0 || >=24.0.0"
+      },
+      "peerDependencies": {
+        "@angular/common": "21.2.19",
+        "@angular/compiler": "21.2.19",
+        "@angular/core": "21.2.19",
+        "@angular/platform-browser": "21.2.19",
+        "rxjs": "^6.5.3 || ^7.4.0"
+      }
+    },
     "node_modules/@angular/router": {
       "version": "21.2.16",
       "resolved": "https://registry.npmjs.org/@angular/router/-/router-21.2.16.tgz",
@@ -621,6 +644,26 @@
         "rxjs": "^6.5.3 || ^7.4.0"
       }
     },
+    "node_modules/@angular/ssr": {
+      "version": "21.2.20",
+      "resolved": "https://registry.npmjs.org/@angular/ssr/-/ssr-21.2.20.tgz",
+      "integrity": "sha512-MZn7Hssm2EYaQ8zWGD+o2fzVs4BLGHLXSg2L7JBmAjlXhSyJeBYw2PUOzSX4gqCNF6wR8ikmJJTel0q8Bo6oow==",
+      "license": "MIT",
+      "dependencies": {
+        "tslib": "^2.3.0"
+      },
+      "peerDependencies": {
+        "@angular/common": "^21.0.0",
+        "@angular/core": "^21.0.0",
+        "@angular/platform-server": "^21.0.0",
+        "@angular/router": "^21.0.0"
+      },
+      "peerDependenciesMeta": {
+        "@angular/platform-server": {
+          "optional": true
+        }
+      }
+    },
     "node_modules/@asamuzakjp/css-color": {
       "version": "3.2.0",
       "resolved": "https://registry.npmjs.org/@asamuzakjp/css-color/-/css-color-3.2.0.tgz",
@@ -1060,43 +1103,6 @@
         "node": ">=18"
       }
     },
-    "node_modules/@emnapi/core": {
-      "version": "1.11.0",
-      "resolved": "https://registry.npmjs.org/@emnapi/core/-/core-1.11.0.tgz",
-      "integrity": "sha512-l9Oo58x0HOP5znGzVhYW9U3e5wVuA4LAZU2AGezTmkhO1CgQRFDhDg4nneHsu/t3WniXg9QrG2nIXL/ZS8ln8Q==",
-      "dev": true,
-      "license": "MIT",
-      "optional": true,
-      "peer": true,
-      "dependencies": {
-        "@emnapi/wasi-threads": "1.2.2",
-        "tslib": "^2.4.0"
-      }
-    },
-    "node_modules/@emnapi/runtime": {
-      "version": "1.11.0",
-      "resolved": "https://registry.npmjs.org/@emnapi/runtime/-/runtime-1.11.0.tgz",
-      "integrity": "sha512-55coeOFKHv1ywEcUXJtWU5f+Jr/W5tZDvZig8DLKSwUN1JpROQ4rk/SNOQiFWmaR/VKF4zuFyW1B8JduOSv6Pg==",
-      "dev": true,
-      "license": "MIT",
-      "optional": true,
-      "peer": true,
-      "dependencies": {
-        "tslib": "^2.4.0"
-      }
-    },
-    "node_modules/@emnapi/wasi-threads": {
-      "version": "1.2.2",
-      "resolved": "https://registry.npmjs.org/@emnapi/wasi-threads/-/wasi-threads-1.2.2.tgz",
-      "integrity": "sha512-c95qOXkHdydNKhscBTebqEC1CVAZpyqOfVfBzQ1qgzyl3gfeldUjIggDbIZgDKsHLgnsM+igH7TJ/eAasaVuMA==",
-      "dev": true,
-      "license": "MIT",
-      "optional": true,
-      "peer": true,
-      "dependencies": {
-        "tslib": "^2.4.0"
-      }
-    },
     "node_modules/@esbuild/aix-ppc64": {
       "version": "0.27.3",
       "resolved": "https://registry.npmjs.org/@esbuild/aix-ppc64/-/aix-ppc64-0.27.3.tgz",
@@ -8732,6 +8738,15 @@
         }
       }
     },
+    "node_modules/xhr2": {
+      "version": "0.2.1",
+      "resolved": "https://registry.npmjs.org/xhr2/-/xhr2-0.2.1.tgz",
+      "integrity": "sha512-sID0rrVCqkVNUn8t6xuv9+6FViXjUVXq8H5rWOH2rz9fDNQEd4g0EA2XlcEdJXRz5BMEn4O1pJFdT+z4YHhoWw==",
+      "license": "MIT",
+      "engines": {
+        "node": ">= 6"
+      }
+    },
     "node_modules/xml-name-validator": {
       "version": "5.0.0",
       "resolved": "https://registry.npmjs.org/xml-name-validator/-/xml-name-validator-5.0.0.tgz",