fix: derive SERVER_VERSION from package.json

dbmole reported a hardcoded SERVER_VERSION of 0.1.0 while the package was
already published as 0.1.1: the constant had drifted because a bump has to
touch two places. Both servers now read the version from package.json
(resolveJsonModule + a JSON import attribute), so a release updates one
place and the reported version can no longer fall behind.

Add a dbmole guard test that add_connection publishes a non-empty
inputSchema with the expected required fields, mirroring esmole, so a future
`.superRefine` on the schema cannot silently empty it.

packages/esmole-mcp/test/unit/server.test.ts

@@ -5,6 +5,7 @@ import { Client } from '@modelcontextprotocol/sdk/client/index.js'
 import { InMemoryTransport } from '@modelcontextprotocol/sdk/inMemory.js'
 import type { McpServer } from '@modelcontextprotocol/sdk/server/mcp.js'
 import { afterEach, beforeEach, describe, expect, it } from 'vitest'
+import pkg from '../../package.json' with { type: 'json' }
 import { createManager } from '../../src/manager.js'
 import { createRegistry } from '../../src/registry.js'
 import { createServer, SERVER_VERSION } from '../../src/server.js'
@@ -27,8 +28,8 @@ describe('createServer', () => {
         rmSync(dir, { recursive: true, force: true })
     })
 
-    it('exports SERVER_VERSION', () => {
-        expect(SERVER_VERSION).toBe('0.1.1')
+    it('reports the package version over MCP', () => {
+        expect(SERVER_VERSION).toBe(pkg.version)
     })
 
     it('registers exactly the ten tools and names the server esmole-mcp', async () => {