fix(metassr-build): replace panicking Manifest::from() with proper error handling

crates/metassr-build/src/server/manifest.rs

@@ -92,15 +92,18 @@ impl Manifest {
     pub fn get(&self, route: &str) -> Option<&ManifestEntry> {
         self.routes.get(route)
     }
-}
-
-impl<S: AsRef<OsStr> + ?Sized> From<&S> for Manifest {
-    fn from(path: &S) -> Self {
-        let manifest_filename = "manifest.json";
-        let path = PathBuf::from(path).join(manifest_filename);
-        let content = read_to_string(path).unwrap();
 
-        serde_json::from_str(&content).unwrap()
+    /// Load manifest from path with proper error handling
+    pub fn load<S: AsRef<OsStr> + ?Sized>(path: &S) -> Result<Self> {
+        let path = PathBuf::from(path).join("manifest.json");
+        let content = read_to_string(&path).map_err(|e| {
+            anyhow!(
+                "Could not read manifest.json at {:?}: {}. Did you run `metassr build` first?",
+                path,
+                e
+            )
+        })?;
+        serde_json::from_str(&content).map_err(|e| anyhow!("manifest.json is malformed: {}", e))
     }
 }
 

crates/metassr-build/src/server/renderer/page.rs

@@ -1,6 +1,6 @@
 use std::ffi::OsStr;
 
-use anyhow::Result;
+use anyhow::{anyhow, Result};
 
 use metassr_fs_analyzer::dist_dir::PageEntry;
 use metassr_utils::cache_dir::CacheDir;
@@ -23,10 +23,13 @@ impl PageRenderer {
         manifest_parent: &S,
         route: &str,
     ) -> Result<Self> {
-        let manifest = Manifest::from(manifest_parent);
+        let manifest = Manifest::load(manifest_parent)?;
 
         let cache = CacheDir::new(&manifest.global.cache)?;
-        let entry = manifest.get(route).unwrap().clone();
+        let entry = manifest
+            .get(route)
+            .ok_or_else(|| anyhow!("No manifest entry found for route: {:?}", route))?
+            .clone();
 
         let exec = RenderExec::new(entry.id, &entry.renderer)?;
         let body = exec.exec()?;