Improve chat encryption, delivery, and session handling

Adds robust session serialization/deserialization for ratchet state, session cleanup for corrupted data, and improved error handling in chat encryption hooks. Enhances chat delivery to support both local and remote recipients, ensures conversation creation, and adds timeouts to key fetches. Also introduces utilities for deleting and clearing encrypted session data from storage.

src/app/api/chat/keys/fetch/route.ts

@@ -12,14 +12,26 @@ export async function GET(request: NextRequest) {
 
     const handle = searchParams.get('handle');
 
-    // Helper to fetch and check
+    // Helper to fetch and check with timeout
     const tryFetch = async (url: string) => {
         console.log(`[Proxy] Fetching keys from: ${url}`);
-        const res = await fetch(url, { headers: { 'Accept': 'application/json' } });
-        if (res.ok) return await res.json();
-        const text = await res.text();
-        console.warn(`[Proxy] Fetch failed for ${url} (${res.status}): ${text}`);
-        return null;
+        try {
+            const controller = new AbortController();
+            const id = setTimeout(() => controller.abort(), 5000); // 5s timeout
+            const res = await fetch(url, {
+                headers: { 'Accept': 'application/json' },
+                signal: controller.signal
+            });
+            clearTimeout(id);
+
+            if (res.ok) return await res.json();
+            const text = await res.text();
+            console.warn(`[Proxy] Fetch failed for ${url} (${res.status}): ${text}`);
+            return null;
+        } catch (err: any) {
+            console.warn(`[Proxy] Fetch error for ${url}: ${err.name} - ${err.message}`);
+            return null;
+        }
     };
 
     // 1. Try Primary DID