feat: optimize performance and SEO, integrate Lighthouse CI

- Integrated imgproxy for centralized image optimization
- Implemented Lighthouse CI in Gitea pipeline with native Chromium
- Reached 100/100 SEO score by fixing canonicals, hreflang, and link text
- Optimized LCP by forcing Hero component visibility until hydration
- Decoupled analytics into an async shell to reduce TTI

config/lighthouserc.json

@@ -0,0 +1,52 @@
+{
+  "ci": {
+    "collect": {
+      "numberOfRuns": 1,
+      "settings": {
+        "preset": "desktop",
+        "onlyCategories": ["performance", "accessibility", "best-practices", "seo"],
+        "chromeFlags": "--no-sandbox --disable-setuid-sandbox"
+      }
+    },
+    "assert": {
+      "assertions": {
+        "categories:performance": [
+          "error",
+          {
+            "minScore": 0.8
+          }
+        ],
+        "categories:accessibility": [
+          "error",
+          {
+            "minScore": 0.9
+          }
+        ],
+        "categories:best-practices": [
+          "error",
+          {
+            "minScore": 0.9
+          }
+        ],
+        "categories:seo": [
+          "error",
+          {
+            "minScore": 0.9
+          }
+        ],
+        "first-contentful-paint": [
+          "warn",
+          {
+            "maxNumericValue": 2000
+          }
+        ],
+        "interactive": [
+          "warn",
+          {
+            "maxNumericValue": 3500
+          }
+        ]
+      }
+    }
+  }
+}