Fix/percistent mcp connection (#392)

* feat(oauth): add support for refresh tokens in OAuth flow and update database schema

* feat(prompts): add MCP prompts and corresponding functionality for prompt retrieval

* feat(auth): enhance error handling for refresh token operations and validation

extensions/general/mcp-server/__tests__/prompts.test.ts

@@ -0,0 +1,40 @@
+import { describe, it, expect } from 'vitest'
+import { prompts, findPrompt } from '../prompts'
+
+describe('mcp prompt registry', () => {
+  it('exposes the five single-action prompts', () => {
+    expect(prompts).toHaveLength(5)
+    const names = prompts.map((p) => p.name).sort()
+    expect(names).toEqual([
+      'cash_today',
+      'last_month_result',
+      'uncategorized_count',
+      'vat_due',
+      'whats_overdue',
+    ])
+  })
+
+  it('every prompt has description and non-trivial text', () => {
+    for (const p of prompts) {
+      expect(p.description).toBeTruthy()
+      expect(p.text.length).toBeGreaterThan(40)
+    }
+  })
+
+  it('prompt names are snake_case and unique', () => {
+    const seen = new Set<string>()
+    for (const p of prompts) {
+      expect(p.name).toMatch(/^[a-z][a-z0-9_]*$/)
+      expect(seen.has(p.name)).toBe(false)
+      seen.add(p.name)
+    }
+  })
+
+  it('findPrompt returns the matching prompt', () => {
+    expect(findPrompt('vat_due')?.name).toBe('vat_due')
+  })
+
+  it('findPrompt returns null for an unknown name', () => {
+    expect(findPrompt('does_not_exist')).toBeNull()
+  })
+})