feat: Implement end-to-end encrypted chat with new API routes, crypto utilities, and UI components.

src/app/.well-known/synapsis/chat/[did]/route.ts

@@ -0,0 +1,47 @@
+
+import { NextRequest, NextResponse } from 'next/server';
+import { db } from '@/db';
+import { chatDeviceBundles } from '@/db/schema';
+import { eq } from 'drizzle-orm';
+
+export async function GET(
+    request: NextRequest,
+    { params }: { params: Promise<{ did: string }> }
+) {
+    const { did } = await params;
+
+    // 1. Fetch all devices for this DID
+    const bundles = await db.query.chatDeviceBundles.findMany({
+        where: eq(chatDeviceBundles.did, did),
+        with: {
+            oneTimeKeys: {
+                limit: 5, // Return a few keys; client picks one
+                // Ideally we pick non-conflicted ones or random ones
+            }
+        }
+    });
+
+    if (!bundles || bundles.length === 0) {
+        return NextResponse.json([], { status: 404 });
+    }
+
+    // 2. Format Response
+    const response = bundles.map(b => ({
+        did: b.did,
+        deviceId: b.deviceId,
+        identityKey: b.identityKey, // Base64 X25519
+        signedPreKey: JSON.parse(b.signedPreKey),
+        oneTimeKeys: b.oneTimeKeys.map(k => ({
+            id: k.keyId,
+            key: k.publicKey
+        })),
+        signature: b.signature // ECDSA signature of this bundle
+    }));
+
+    return NextResponse.json(response, {
+        headers: {
+            'Access-Control-Allow-Origin': '*', // Federation Header
+            'Cache-Control': 'max-age=60' // Cache for 1 min
+        }
+    });
+}