acp: Add agent license if available from the registry (#64178)

The JetBrains team started added links to the relevant license terms for
each agent. Seems worth linking out to if we have it.

Release Notes:

- N/A

crates/agent_servers/src/custom.rs

@@ -361,6 +361,7 @@ mod tests {
                         version: SharedString::from("1.0.0"),
                         repository: None,
                         website: None,
+                        license_url: None,
                         icon_path: None,
                     },
                     package: id,

crates/agent_ui/src/agent_registry_ui.rs

@@ -444,6 +444,27 @@ impl AgentRegistryPage {
             })
         });
 
+        let license_button = agent.license_url().map(|license_url| {
+            let license_url = license_url.clone();
+            let license_url_for_click = license_url.clone();
+            IconButton::new(
+                SharedString::from(format!("agent-license-{}", agent.id())),
+                IconName::FileTextOutlined,
+            )
+            .icon_size(IconSize::Small)
+            .tooltip(move |_, cx| {
+                Tooltip::with_meta(
+                    "View Agent License or Terms of Service",
+                    None,
+                    license_url.clone(),
+                    cx,
+                )
+            })
+            .on_click(move |_, _, cx| {
+                cx.open_url(&license_url_for_click);
+            })
+        });
+
         AgentRegistryCard::new()
             .child(
                 h_flex()
@@ -483,7 +504,8 @@ impl AgentRegistryPage {
                                     .truncate(),
                             )
                             .when_some(repository_button, |this, button| this.child(button))
-                            .when_some(website_button, |this, button| this.child(button)),
+                            .when_some(website_button, |this, button| this.child(button))
+                            .when_some(license_button, |this, button| this.child(button)),
                     ),
             )
     }

crates/project/src/agent_registry_store.rs

@@ -32,6 +32,7 @@ pub struct RegistryAgentMetadata {
     pub version: SharedString,
     pub repository: Option<SharedString>,
     pub website: Option<SharedString>,
+    pub license_url: Option<SharedString>,
     pub icon_path: Option<SharedString>,
 }
 
@@ -88,6 +89,10 @@ impl RegistryAgent {
         self.metadata().website.as_ref()
     }
 
+    pub fn license_url(&self) -> Option<&SharedString> {
+        self.metadata().license_url.as_ref()
+    }
+
     pub fn icon_path(&self) -> Option<&SharedString> {
         self.metadata().icon_path.as_ref()
     }
@@ -396,6 +401,7 @@ async fn build_registry_agents(
             version: entry.version.into(),
             repository: entry.repository.map(Into::into),
             website: entry.website.map(Into::into),
+            license_url: entry.license_url.map(Into::into),
             icon_path,
         };
 
@@ -643,6 +649,8 @@ struct RegistryEntry {
     #[serde(default)]
     website: Option<String>,
     #[serde(default)]
+    license_url: Option<String>,
+    #[serde(default)]
     icon: Option<String>,
     distribution: RegistryDistribution,
 }

crates/project/src/agent_server_store.rs

@@ -1765,6 +1765,7 @@ mod tests {
                 version: SharedString::from(version.to_string()),
                 repository: None,
                 website: None,
+                license_url: None,
                 icon_path: None,
             },
             package: id,