Implement official Prisma solution for client generation

Following Prisma's official documentation for deployment caching issues:
https://www.prisma.io/docs/orm/more/help-and-troubleshooting/vercel-caching-issue

Changes:
- Add 'prisma generate' to build script (official Prisma recommendation)
- Add postinstall script for automatic client generation
- Remove custom stub generator workaround
- Keep runtime Prisma client generation in entrypoint.sh for reliability
- Add openssl to runtime container (required for Prisma engines)

This follows Prisma best practices: explicitly run prisma generate during the
build process to ensure Prisma Client is always up-to-date. The entrypoint
script regenerates the client at runtime to guarantee engine availability in
the production environment.

scripts/generate-prisma-stub.js

@@ -1,144 +0,0 @@
-#!/usr/bin/env node
-
-/**
- * This script generates a minimal Prisma Client stub to allow building
- * when the Prisma engines cannot be downloaded (e.g., network restrictions).
- *
- * The actual Prisma engines must be available at runtime.
- */
-
-const fs = require('fs');
-const path = require('path');
-
-const clientDir = path.join(__dirname, '..', 'node_modules', '.prisma', 'client');
-
-// Ensure directory exists
-fs.mkdirSync(clientDir, { recursive: true });
-
-// Generate minimal client files
-const indexContent = `
-// Auto-generated stub for build-time type checking
-// Real Prisma Client will be generated at runtime
-
-class PrismaClient {
-  constructor(options = {}) {
-    this.user = createModelProxy('User');
-    this.session = createModelProxy('Session');
-    this.oAuthState = createModelProxy('OAuthState');
-    this.setting = createModelProxy('Setting');
-    this.accessList = createModelProxy('AccessList');
-    this.accessListEntry = createModelProxy('AccessListEntry');
-    this.certificate = createModelProxy('Certificate');
-    this.proxyHost = createModelProxy('ProxyHost');
-    this.redirectHost = createModelProxy('RedirectHost');
-    this.deadHost = createModelProxy('DeadHost');
-    this.apiToken = createModelProxy('ApiToken');
-    this.auditEvent = createModelProxy('AuditEvent');
-  }
-
-  async $connect() {
-    throw new Error('Prisma Client stub - engines not available at build time');
-  }
-
-  async $disconnect() {
-    return Promise.resolve();
-  }
-
-  async $executeRaw() {
-    throw new Error('Prisma Client stub - engines not available at build time');
-  }
-
-  async $queryRaw() {
-    throw new Error('Prisma Client stub - engines not available at build time');
-  }
-
-  async $transaction() {
-    throw new Error('Prisma Client stub - engines not available at build time');
-  }
-}
-
-function createModelProxy(modelName) {
-  return new Proxy({}, {
-    get() {
-      throw new Error(\`Prisma Client stub - \${modelName} operations not available at build time\`);
-    }
-  });
-}
-
-exports.PrismaClient = PrismaClient;
-exports.Prisma = {
-  ModelName: {
-    User: 'User',
-    Session: 'Session',
-    OAuthState: 'OAuthState',
-    Setting: 'Setting',
-    AccessList: 'AccessList',
-    AccessListEntry: 'AccessListEntry',
-    Certificate: 'Certificate',
-    ProxyHost: 'ProxyHost',
-    RedirectHost: 'RedirectHost',
-    DeadHost: 'DeadHost',
-    ApiToken: 'ApiToken',
-    AuditEvent: 'AuditEvent'
-  }
-};
-`;
-
-const indexDtsContent = `
-// Auto-generated stub for build-time type checking
-
-export class PrismaClient {
-  constructor(options?: any);
-  user: any;
-  session: any;
-  oAuthState: any;
-  setting: any;
-  accessList: any;
-  accessListEntry: any;
-  certificate: any;
-  proxyHost: any;
-  redirectHost: any;
-  deadHost: any;
-  apiToken: any;
-  auditEvent: any;
-  $connect(): Promise<void>;
-  $disconnect(): Promise<void>;
-  $executeRaw(query: any, ...values: any[]): Promise<any>;
-  $queryRaw(query: any, ...values: any[]): Promise<any>;
-  $transaction(fn: any): Promise<any>;
-}
-
-export namespace Prisma {
-  export const ModelName: {
-    User: 'User';
-    Session: 'Session';
-    OAuthState: 'OAuthState';
-    Setting: 'Setting';
-    AccessList: 'AccessList';
-    AccessListEntry: 'AccessListEntry';
-    Certificate: 'Certificate';
-    ProxyHost: 'ProxyHost';
-    RedirectHost: 'RedirectHost';
-    DeadHost: 'DeadHost';
-    ApiToken: 'ApiToken';
-    AuditEvent: 'AuditEvent';
-  };
-}
-`;
-
-const defaultJsContent = indexContent;
-const defaultDtsContent = indexDtsContent;
-
-// Write files
-fs.writeFileSync(path.join(clientDir, 'index.js'), indexContent);
-fs.writeFileSync(path.join(clientDir, 'index.d.ts'), indexDtsContent);
-fs.writeFileSync(path.join(clientDir, 'default.js'), defaultJsContent);
-fs.writeFileSync(path.join(clientDir, 'default.d.ts'), defaultDtsContent);
-fs.writeFileSync(path.join(clientDir, 'edge.js'), defaultJsContent);
-fs.writeFileSync(path.join(clientDir, 'edge.d.ts'), defaultDtsContent);
-fs.writeFileSync(path.join(clientDir, 'wasm.js'), defaultJsContent);
-fs.writeFileSync(path.join(clientDir, 'wasm.d.ts'), defaultDtsContent);
-fs.writeFileSync(path.join(clientDir, 'index-browser.js'), defaultJsContent);
-
-console.log('✓ Generated Prisma Client stub for build');
-console.log('⚠️  Note: Actual Prisma engines must be available at runtime');