feat: per-page titles, OG/SEO tags, HOST/PORT env vars, BASE_URL in config

crates/application/src/config.rs

@@ -1,6 +1,7 @@
 #[derive(Clone)]
 pub struct AppConfig {
     pub allow_registration: bool,
+    pub base_url: String,
 }
 
 impl AppConfig {
@@ -8,6 +9,8 @@ impl AppConfig {
         let allow_registration = std::env::var("ALLOW_REGISTRATION")
             .map(|v| v == "true" || v == "1")
             .unwrap_or(false);
-        Self { allow_registration }
+        let base_url = std::env::var("BASE_URL")
+            .unwrap_or_else(|_| "http://localhost:3000".to_string());
+        Self { allow_registration, base_url }
     }
 }

crates/application/src/ports.rs

@@ -7,6 +7,8 @@ pub struct HtmlPageContext {
     pub user_id: Option<Uuid>,
     pub register_enabled: bool,
     pub rss_url: String,
+    pub page_title: String,
+    pub canonical_url: String,
 }
 
 impl HtmlPageContext {