add dev resources; plumb GUI_ENV_FILE/API_ENV_FILE/API_DESI_DATA into run targets

api/src/config.rs

@@ -1,5 +1,10 @@
+use std::path::PathBuf;
+
 pub struct Config {
     pub bind_addr: String,
+    /// Path to a DESI data file (JSON) to serve; `None` falls back to the
+    /// built-in placeholder catalogs.
+    pub desi_data: Option<PathBuf>,
 }
 
 impl Config {
@@ -7,6 +12,14 @@ impl Config {
         let bind_addr =
             std::env::var("API_BIND_ADDR").unwrap_or_else(|_| "0.0.0.0:8080".to_string());
 
-        Ok(Self { bind_addr })
+        let desi_data = std::env::var("API_DESI_DATA")
+            .ok()
+            .filter(|s| !s.is_empty())
+            .map(PathBuf::from);
+
+        Ok(Self {
+            bind_addr,
+            desi_data,
+        })
     }
 }