fix: address PR review feedback for MCP tools support

- Avoid logging sensitive cfg.Args in ConnectServer; log args_count instead
- Sanitize server/tool name components in MCPTool.Name() to ensure valid
  identifiers for downstream providers (lowercase, [a-z0-9_-] only)
- Add slack as 5th MCP server example in config.example.json
- Move Dockerfile.full and docker-compose.full.yml into docker/ directory
  for consistency with existing docker/Dockerfile and docker/docker-compose.yml
- Fix all Makefile docker-* targets to reference correct compose file paths
- Fix docker/docker-compose.full.yml build context (.. ) and volume paths
- Fix scripts/test-docker-mcp.sh compose file path and replace cowsay test
  with actual @modelcontextprotocol/server-filesystem MCP server test

pkg/mcp/manager.go

@@ -243,9 +243,9 @@ func (m *Manager) ConnectServer(
 ) error {
 	logger.InfoCF("mcp", "Connecting to MCP server",
 		map[string]any{
-			"server":  name,
-			"command": cfg.Command,
-			"args":    cfg.Args,
+			"server":     name,
+			"command":    cfg.Command,
+			"args_count": len(cfg.Args),
 		})
 
 	// Create client