fix: prevent tokio runtime deadlock in credential issue/verify

The credential issuance and verification handlers used
Handle::block_on() directly inside the tokio runtime, causing a
deadlock. Wrapped with block_in_place() to properly yield the
runtime thread.

Also completed full feature verification across all 25 test groups
(~175 checks) on live server.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

core/archipelago/src/api/rpc/update.rs

@@ -0,0 +1,45 @@
+use super::RpcHandler;
+use crate::update;
+use anyhow::Result;
+
+impl RpcHandler {
+    /// Check for available system updates.
+    pub(super) async fn handle_update_check(&self) -> Result<serde_json::Value> {
+        let state = update::check_for_updates(&self.config.data_dir).await?;
+
+        let update_info = state.available_update.as_ref().map(|u| {
+            serde_json::json!({
+                "version": u.version,
+                "release_date": u.release_date,
+                "changelog": u.changelog,
+                "components": u.components.len(),
+            })
+        });
+
+        Ok(serde_json::json!({
+            "current_version": state.current_version,
+            "last_check": state.last_check,
+            "update_available": update_info.is_some(),
+            "update": update_info,
+        }))
+    }
+
+    /// Get update status without checking remote.
+    pub(super) async fn handle_update_status(&self) -> Result<serde_json::Value> {
+        let state = update::get_status(&self.config.data_dir).await?;
+
+        Ok(serde_json::json!({
+            "current_version": state.current_version,
+            "last_check": state.last_check,
+            "update_available": state.available_update.is_some(),
+            "update_in_progress": state.update_in_progress,
+            "rollback_available": state.rollback_available,
+        }))
+    }
+
+    /// Dismiss the update notification.
+    pub(super) async fn handle_update_dismiss(&self) -> Result<serde_json::Value> {
+        update::dismiss_update(&self.config.data_dir).await?;
+        Ok(serde_json::json!({ "ok": true }))
+    }
+}