feat: added langflow, langfuse and langgraph integrations (#17)

Co-authored-by: Sharang Parnerkar <parnerkarsharang@gmail.com>
Reviewed-on: #17

src/models/services.rs

@@ -0,0 +1,43 @@
+use serde::{Deserialize, Serialize};
+
+/// Frontend-facing URLs for developer tool services.
+///
+/// Provided as a context signal in `AppShell` so that developer pages
+/// can read the configured URLs without threading props through layouts.
+/// An empty string indicates the service is not configured.
+#[derive(Debug, Clone, Default, PartialEq, Serialize, Deserialize)]
+pub struct ServiceUrlsContext {
+    /// LangGraph agent builder URL (empty if not configured)
+    pub langgraph_url: String,
+    /// LangFlow visual workflow builder URL (empty if not configured)
+    pub langflow_url: String,
+    /// Langfuse observability URL (empty if not configured)
+    pub langfuse_url: String,
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use pretty_assertions::assert_eq;
+
+    #[test]
+    fn default_urls_are_empty() {
+        let ctx = ServiceUrlsContext::default();
+        assert_eq!(ctx.langgraph_url, "");
+        assert_eq!(ctx.langflow_url, "");
+        assert_eq!(ctx.langfuse_url, "");
+    }
+
+    #[test]
+    fn serde_round_trip() {
+        let ctx = ServiceUrlsContext {
+            langgraph_url: "http://localhost:8123".into(),
+            langflow_url: "http://localhost:7860".into(),
+            langfuse_url: "http://localhost:3000".into(),
+        };
+        let json = serde_json::to_string(&ctx).expect("serialize ServiceUrlsContext");
+        let back: ServiceUrlsContext =
+            serde_json::from_str(&json).expect("deserialize ServiceUrlsContext");
+        assert_eq!(ctx, back);
+    }
+}