feat: integrate Nostr keypair generation with LNBits user accounts

- Added Nostr private key storage to the accounts table via a new migration.
- Updated Account model to include Nostr private key field.
- Modified user creation process to automatically generate Nostr keypairs.
- Introduced new API endpoints for retrieving Nostr public keys and user information including private keys.
- Implemented tests to verify Nostr keypair generation and account model updates.

misc-aio/NOSTR_INTEGRATION.md

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+# Nostr Integration for LNBits Users
+
+This document describes the changes made to integrate Nostr keypairs with LNBits user accounts.
+
+## Overview
+
+The integration adds Nostr keypair generation to user accounts, allowing each user to have a unique Nostr identity. The private key is stored securely in the database, while the public key is derived and made available through the API.
+
+## Changes Made
+
+### 1. Database Migration
+
+**File**: `lnbits/core/migrations.py`
+- Added `m034_add_nostr_private_key_to_accounts()` migration
+- Adds `prvkey` column to the `accounts` table for Nostr private keys
+
+### 2. Model Updates
+
+**File**: `lnbits/core/models/users.py`
+- Added `prvkey` field to `Account` model for Nostr private key
+- The existing `pubkey` field is now used to store the Nostr public key
+
+### 3. CRUD Operations
+
+**File**: `lnbits/core/crud/users.py`
+- Updated `get_user_from_account()` to use the existing pubkey field (now contains Nostr public key)
+- Updated `get_accounts()` SQL query to include `prvkey` field
+
+### 4. API Endpoints
+
+**File**: `lnbits/core/views/user_api.py`
+- Modified user creation to automatically generate Nostr keypair and set the pubkey field
+- Added new endpoint `/users/api/v1/nostr/pubkeys` to get all user public keys
+- Endpoint requires admin privileges and returns:
+  ```json
+  [
+    {
+      "user_id": "user_id",
+      "username": "username", 
+      "nostr_public_key": "public_key_hex"
+    }
+  ]
+  ```
+
+### 5. Command Line Interface
+
+**File**: `lnbits/commands.py`
+- Updated `create_user` command to generate Nostr keypair
+- Displays the generated public key when creating users via CLI
+
+## API Usage
+
+### Creating a User (Automatically generates Nostr keypair)
+
+```bash
+POST /users/api/v1/user
+Content-Type: application/json
+
+{
+  "username": "testuser",
+  "email": "test@example.com",
+  "password": "password123",
+  "password_repeat": "password123"
+}
+```
+
+### Getting All User Public Keys
+
+```bash
+GET /users/api/v1/nostr/pubkeys
+Authorization: Bearer <admin_token>
+
+Response:
+[
+  {
+    "user_id": "abc123",
+    "username": "user1",
+    "pubkey": "02a1b2c3d4e5f6..."
+  },
+  {
+    "user_id": "def456", 
+    "username": "user2",
+    "pubkey": "03b2c3d4e5f6a1..."
+  }
+]
+```
+
+### Getting Individual User (includes Nostr public key)
+
+```bash
+GET /users/api/v1/user/{user_id}
+
+Response:
+{
+  "id": "abc123",
+  "username": "user1",
+  "email": "user1@example.com",
+  "pubkey": "02a1b2c3d4e5f6...",  # This is the Nostr public key
+  "created_at": "2024-01-01T00:00:00Z",
+  "updated_at": "2024-01-01T00:00:00Z",
+  ...
+}
+```
+
+## Security Considerations
+
+1. **Private Key Storage**: Nostr private keys are stored in the `prvkey` field but are never exposed through the API
+2. **Public Key Storage**: Nostr public keys are stored directly in the `pubkey` field for efficiency
+3. **Admin Access**: The public key listing endpoint requires admin privileges
+4. **Consistent Naming**: `pubkey` and `prvkey` provide clear, consistent field names
+
+## Migration
+
+To apply the database changes:
+
+1. Run the migration: `python -m lnbits db migrate`
+2. The migration will add the `prvkey` column to existing accounts for Nostr private keys
+3. New users will automatically get Nostr keypairs generated
+
+## Testing
+
+Use the provided test script to verify the integration:
+
+```bash
+python test_nostr_integration.py
+```
+
+## Dependencies
+
+The integration uses the existing `lnbits.utils.nostr` module which provides:
+- `generate_keypair()`: Generates new Nostr keypairs
+- `PrivateKey` class: For key manipulation and public key derivation
+
+## Future Enhancements
+
+Potential improvements could include:
+1. NIP-19 encoding support (npub/nsec format)
+2. Nostr event signing capabilities
+3. Integration with Nostr relays for user discovery
+4. User profile metadata storage