Add encrypted key support for chat and nodes

Introduces encrypted private key storage for nodes and users, updates chat message schema to support sender-side encryption, and adds supporting libraries and tests for cryptographic signing and identity unlock flows. Includes new database migrations, API route updates, and React components for identity unlock prompts.

src/app/api/auth/login/route.ts

@@ -37,6 +37,9 @@ export async function POST(request: Request) {
                 id: user.id,
                 handle: user.handle,
                 displayName: user.displayName,
+                did: user.did,
+                publicKey: user.publicKey,
+                privateKeyEncrypted: user.privateKeyEncrypted, // Client will decrypt with password
             },
         });
     } catch (error) {

src/app/api/auth/me/route.ts

@@ -33,6 +33,9 @@ export async function GET() {
                 avatarUrl: session.user.avatarUrl,
                 bio: session.user.bio,
                 website: session.user.website,
+                did: session.user.did,
+                publicKey: session.user.publicKey,
+                privateKeyEncrypted: session.user.privateKeyEncrypted,
             },
         });
     } catch (error) {

src/app/api/auth/register/route.ts

@@ -68,6 +68,9 @@ export async function POST(request: Request) {
                 id: user.id,
                 handle: user.handle,
                 displayName: user.displayName,
+                did: user.did,
+                publicKey: user.publicKey,
+                privateKeyEncrypted: user.privateKeyEncrypted, // Client will decrypt with password
             },
         });
     } catch (error) {