Go: add new provider minimax (#14296)

### What problem does this PR solve?

1. Add new provider minimax
2. Add new command: CHECK INSTANCE 'instance_name' FROM 'provider_name';
```
RAGFlow(user)> check instance 'test' from 'minimax';
SUCCESS
```

### Type of change

- [x] New Feature (non-breaking change which adds functionality)

Signed-off-by: Jin Hai <haijin.chn@gmail.com>

internal/cli/user_parser.go

@@ -2325,6 +2325,42 @@ func (p *Parser) parseStreamCommand() (*Command, error) {
 	return command, nil
 }
 
+func (p *Parser) parseCheckCommand() (*Command, error) {
+	p.nextToken() // consume CHECK
+
+	if p.curToken.Type != TokenInstance {
+		return nil, fmt.Errorf("expected INSTANCE after CHECK")
+	}
+	p.nextToken()
+
+	if p.curToken.Type != TokenQuotedString {
+		return nil, fmt.Errorf("expected instance name after INSTANCE")
+	}
+	instanceName := p.curToken.Value
+	p.nextToken()
+
+	if p.curToken.Type != TokenFrom {
+		return nil, fmt.Errorf("expected FROM after instance name")
+	}
+	p.nextToken()
+
+	if p.curToken.Type != TokenQuotedString {
+		return nil, fmt.Errorf("expected provider name after FROM")
+	}
+	providerName := p.curToken.Value
+	p.nextToken()
+
+	// Semicolon is optional
+	if p.curToken.Type == TokenSemicolon {
+		p.nextToken()
+	}
+
+	cmd := NewCommand("check_provider_connection")
+	cmd.Params["provider_name"] = providerName
+	cmd.Params["instance_name"] = instanceName
+	return cmd, nil
+}
+
 func (p *Parser) parseUseCommand() (*Command, error) {
 	p.nextToken() // consume USE