feat: implement MCP provider registry and service

- Add provider registry to manage LLM providers (Claude, Codex, Cursor, Gemini).
- Create provider routes for MCP server operations (list, upsert, delete, run).
- Implement MCP service for handling server operations and validations.
- Introduce abstract provider class and MCP provider base for shared functionality.
- Add tests for MCP server operations across different providers and scopes.
- Define shared interfaces and types for MCP functionality.
- Implement utility functions for handling JSON config files and API responses.

server/modules/providers/list/codex/codex-mcp.provider.ts

@@ -0,0 +1,135 @@
+import { mkdir, readFile, writeFile } from 'node:fs/promises';
+import os from 'node:os';
+import path from 'node:path';
+
+import TOML from '@iarna/toml';
+
+import { McpProvider } from '@/modules/providers/shared/mcp/mcp.provider.js';
+import type { McpScope, ProviderMcpServer, UpsertProviderMcpServerInput } from '@/shared/types.js';
+import {
+  AppError,
+  readObjectRecord,
+  readOptionalString,
+  readStringArray,
+  readStringRecord,
+} from '@/shared/utils.js';
+
+const readTomlConfig = async (filePath: string): Promise<Record<string, unknown>> => {
+  try {
+    const content = await readFile(filePath, 'utf8');
+    const parsed = TOML.parse(content) as Record<string, unknown>;
+    return readObjectRecord(parsed) ?? {};
+  } catch (error) {
+    const code = (error as NodeJS.ErrnoException).code;
+    if (code === 'ENOENT') {
+      return {};
+    }
+    throw error;
+  }
+};
+
+const writeTomlConfig = async (filePath: string, data: Record<string, unknown>): Promise<void> => {
+  await mkdir(path.dirname(filePath), { recursive: true });
+  const toml = TOML.stringify(data as never);
+  await writeFile(filePath, toml, 'utf8');
+};
+
+export class CodexMcpProvider extends McpProvider {
+  constructor() {
+    super('codex', ['user', 'project'], ['stdio', 'http']);
+  }
+
+  protected async readScopedServers(scope: McpScope, workspacePath: string): Promise<Record<string, unknown>> {
+    const filePath = scope === 'user'
+      ? path.join(os.homedir(), '.codex', 'config.toml')
+      : path.join(workspacePath, '.codex', 'config.toml');
+    const config = await readTomlConfig(filePath);
+    return readObjectRecord(config.mcp_servers) ?? {};
+  }
+
+  protected async writeScopedServers(
+    scope: McpScope,
+    workspacePath: string,
+    servers: Record<string, unknown>,
+  ): Promise<void> {
+    const filePath = scope === 'user'
+      ? path.join(os.homedir(), '.codex', 'config.toml')
+      : path.join(workspacePath, '.codex', 'config.toml');
+    const config = await readTomlConfig(filePath);
+    config.mcp_servers = servers;
+    await writeTomlConfig(filePath, config);
+  }
+
+  protected buildServerConfig(input: UpsertProviderMcpServerInput): Record<string, unknown> {
+    if (input.transport === 'stdio') {
+      if (!input.command?.trim()) {
+        throw new AppError('command is required for stdio MCP servers.', {
+          code: 'MCP_COMMAND_REQUIRED',
+          statusCode: 400,
+        });
+      }
+
+      return {
+        command: input.command,
+        args: input.args ?? [],
+        env: input.env ?? {},
+        env_vars: input.envVars ?? [],
+        cwd: input.cwd,
+      };
+    }
+
+    if (!input.url?.trim()) {
+      throw new AppError('url is required for http MCP servers.', {
+        code: 'MCP_URL_REQUIRED',
+        statusCode: 400,
+      });
+    }
+
+    return {
+      url: input.url,
+      bearer_token_env_var: input.bearerTokenEnvVar,
+      http_headers: input.headers ?? {},
+      env_http_headers: input.envHttpHeaders ?? {},
+    };
+  }
+
+  protected normalizeServerConfig(
+    scope: McpScope,
+    name: string,
+    rawConfig: unknown,
+  ): ProviderMcpServer | null {
+    if (!rawConfig || typeof rawConfig !== 'object') {
+      return null;
+    }
+
+    const config = rawConfig as Record<string, unknown>;
+    if (typeof config.command === 'string') {
+      return {
+        provider: 'codex',
+        name,
+        scope,
+        transport: 'stdio',
+        command: config.command,
+        args: readStringArray(config.args),
+        env: readStringRecord(config.env),
+        cwd: readOptionalString(config.cwd),
+        envVars: readStringArray(config.env_vars),
+      };
+    }
+
+    if (typeof config.url === 'string') {
+      return {
+        provider: 'codex',
+        name,
+        scope,
+        transport: 'http',
+        url: config.url,
+        headers: readStringRecord(config.http_headers),
+        bearerTokenEnvVar: readOptionalString(config.bearer_token_env_var),
+        envHttpHeaders: readStringRecord(config.env_http_headers),
+      };
+    }
+
+    return null;
+  }
+}

server/modules/providers/list/codex/codex.provider.ts

@@ -0,0 +1,10 @@
+import { AbstractProvider } from '@/modules/providers/shared/base/abstract.provider.js';
+import { CodexMcpProvider } from '@/modules/providers/list/codex/codex-mcp.provider.js';
+
+export class CodexProvider extends AbstractProvider {
+  readonly mcp = new CodexMcpProvider();
+
+  constructor() {
+    super('codex');
+  }
+}