fix: add explicit embedding initialization with error logging

When embeddings fail to initialize in the MCP server context (e.g., due
to working directory issues), the error was silently swallowed and
smart_ingest would fall back to regular ingest without explanation.

Changes:
- Add init_embeddings() method to Storage for explicit initialization
- Initialize embeddings at MCP server startup with error logging
- Add check_ready() method to EmbeddingService for error access
- Log warning when is_ready() returns false

Now users will see clear error messages like:
"Failed to initialize embedding service: ..."
"Hint: Check FASTEMBED_CACHE_PATH or ensure ~/.fastembed_cache exists"

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

crates/vestige-core/src/embeddings/local.rs

@@ -186,7 +186,18 @@ impl EmbeddingService {
 
     /// Check if the model is ready
     pub fn is_ready(&self) -> bool {
-        get_model().is_ok()
+        match get_model() {
+            Ok(_) => true,
+            Err(e) => {
+                tracing::warn!("Embedding model not ready: {}", e);
+                false
+            }
+        }
+    }
+
+    /// Check if the model is ready and return the error if not
+    pub fn check_ready(&self) -> Result<(), EmbeddingError> {
+        get_model().map(|_| ())
     }
 
     /// Initialize the model (downloads if necessary)

crates/vestige-core/src/storage/sqlite.rs

@@ -1072,6 +1072,20 @@ impl Storage {
         false
     }
 
+    /// Initialize the embedding service explicitly
+    /// Call this at startup to catch initialization errors early
+    #[cfg(feature = "embeddings")]
+    pub fn init_embeddings(&mut self) -> Result<()> {
+        self.embedding_service.init().map_err(|e| {
+            StorageError::Init(format!("Embedding service initialization failed: {}", e))
+        })
+    }
+
+    #[cfg(not(feature = "embeddings"))]
+    pub fn init_embeddings(&mut self) -> Result<()> {
+        Ok(()) // No-op when embeddings feature is disabled
+    }
+
     /// Get query embedding from cache or compute it
     #[cfg(feature = "embeddings")]
     fn get_query_embedding(&self, query: &str) -> Result<Vec<f32>> {