feat: built-in MCP server for AI tool integration

[datlechin]

Summary

• Built-in MCP (Model Context Protocol) server lets AI tools (Claude Desktop, Claude Code, Cursor, Windsurf) query databases through TablePro's existing connections
• 13 tools: list_connections, connect, disconnect, execute_query, list_tables, describe_table, list_databases, list_schemas, get_table_ddl, export_data, get_connection_status, switch_database, switch_schema
• 3 resources: connections list, schema cache, query history
• SSE transport on localhost:23508 via Network.framework (NWListener)
• Full security: respects per-connection AIConnectionPolicy and SafeModeLevel
• Settings tab with enable toggle, port config, row limits, and copy-to-clipboard config snippet
• Query classification extracted to reusable QueryClassifier utility

Architecture

• MCPServer (actor): NWListener lifecycle, session management, SSE
• MCPRouter: HTTP/1.1 parsing, JSON-RPC 2.0 dispatch
• MCPConnectionBridge (actor): MainActor hop to DatabaseManager, driver dispatch
• MCPAuthGuard (actor): AIConnectionPolicy + SafeModeLevel enforcement
• MCPToolHandler / MCPResourceHandler: 13 tool + 3 resource implementations
• MCPServerManager (@mainactor): bridges AppDelegate/Settings to server actor

New files (11)

• Core/MCP/MCPServer.swift, MCPRouter.swift, MCPHTTPParser.swift, MCPSession.swift, MCPMessageTypes.swift
• Core/MCP/MCPConnectionBridge.swift, MCPAuthGuard.swift, MCPToolHandler.swift, MCPResourceHandler.swift, MCPServerManager.swift
• Core/Utilities/SQL/QueryClassifier.swift
• Models/Settings/MCPSettings.swift
• Views/Settings/MCPSettingsView.swift

Modified files (5)

• AppSettingsStorage.swift + AppSettingsManager.swift (MCP settings)
• AppDelegate.swift (server lifecycle)
• SettingsView.swift (MCP tab)
• MainContentCoordinator+QueryAnalysis.swift (delegate to QueryClassifier)

Test plan

• Build succeeds (xcodebuild -scheme TablePro build -skipPackagePluginValidation)
• Enable MCP in Settings, status shows "Running"
• Copy config snippet to Claude Desktop, verify connection
• list_connections returns saved connections without passwords
• connect → list_tables → describe_table → execute_query flow works
• Read-only connection blocks write queries via MCP
• aiPolicy == .never connection returns FORBIDDEN
• Disable MCP in Settings, server stops
• SwiftLint passes