feat: Add eBPF error types with recoverability classification for packet gateway

- Add EbpfError enum with LoadError, AttachError, MapNotFound, MapAccessError, RedisSyncError, RedisFetchError, NotAttached, Timeout, and InvalidData variants
- Add is_recoverable method returning true for MapAccessError, RedisSyncError, RedisFetchError, and Timeout errors
- Add thiserror::Error derive for automatic error trait implementation
- Add interface and map_name fields to AttachError and MapAccessError variants

apps/packet-gateway/src/ebpf_error.rs

@@ -0,0 +1,43 @@
+use thiserror::Error;
+
+#[derive(Debug, Error)]
+pub enum EbpfError {
+    #[error("Failed to load eBPF program: {0}")]
+    LoadError(String),
+    
+    #[error("Failed to attach XDP program to interface {interface}: {message}")]
+    AttachError { interface: String, message: String },
+    
+    #[error("eBPF map '{map_name}' not found")]
+    MapNotFound { map_name: String },
+    
+    #[error("Failed to access eBPF map '{map_name}': {message}")]
+    MapAccessError { map_name: String, message: String },
+    
+    #[error("Failed to sync data to Redis: {0}")]
+    RedisSyncError(String),
+    
+    #[error("Failed to sync data from Redis: {0}")]
+    RedisFetchError(String),
+    
+    #[error("eBPF program detached or not attached")]
+    NotAttached,
+    
+    #[error("eBPF operation timeout: {0}")]
+    Timeout(String),
+    
+    #[error("Invalid eBPF data: {0}")]
+    InvalidData(String),
+}
+
+impl EbpfError {
+    pub fn is_recoverable(&self) -> bool {
+        match self {
+            EbpfError::MapAccessError { .. } => true,
+            EbpfError::RedisSyncError(_) => true,
+            EbpfError::RedisFetchError(_) => true,
+            EbpfError::Timeout(_) => true,
+            _ => false,
+        }
+    }
+}