fix(bdd): every SDK suite silently falls back to a hardcoded address/credentials when its env var is missing

[chengxilo]

Summary

Every BDD step-definition file resolves the server address and root credentials with an "env var or hardcoded default" helper. If the env variable is absent, misspelled, or dropped from a compose overlay, the suite does not fail. Instead, it quietly connects to the default value. Test should be loud when it is broken, we don't need safety or robust here; a fallback turns a configuration bug into either a misleading connection error or, worse, a green run against the wrong server.

The fallbacks also disagree with each other across SDKs, so the same missing variable produces eight different behaviours.

Examples:

iggy/bdd/rust/tests/helpers/cluster.rs

Lines 23 to 35 in 2a8a5c9

	pub fn resolve_server_address(role: &str, port: u16) -> String {
	match (role.to_lowercase().as_str(), port) {
	("leader", 8091) => {
	env::var("IGGY_TCP_ADDRESS_LEADER").unwrap_or_else(|_| "iggy-leader:8091".to_string())
	}
	("follower", 8092) => env::var("IGGY_TCP_ADDRESS_FOLLOWER")
	.unwrap_or_else(|_| "iggy-follower:8092".to_string()),
	("single", 8090) | (_, 8090) => {
	env::var("IGGY_TCP_ADDRESS").unwrap_or_else(|_| "iggy-server:8090".to_string())
	}
	_ => format!("iggy-server:{}", port),
	}
	}

iggy/bdd/go/tests/basic_messaging.go

Lines 53 to 61 in 2a8a5c9

	func (s basicMessagingSteps) givenRunningServer(ctx context.Context) error {
	c := getBasicMessagingCtx(ctx)
	addr := os.Getenv("IGGY_TCP_ADDRESS")
	if addr == "" {
	addr = "127.0.0.1:8090"
	}
	c.serverAddr = &addr
	return nil
	}

iggy/foreign/php/tests/bootstrap.php

Lines 87 to 95 in 2a8a5c9

	function server_host(): string
	{
	return env_or_default('IGGY_HOST', '127.0.0.1');
	}
	function server_port(): int
	{
	return (int) env_or_default('IGGY_PORT', '8090');
	}

Proposed Change

only use the enviroment varaible, if it's not available, just panic.
For example:

pub fn resolve_server_address(role: &str, port: u16) -> String {
     match (role.to_lowercase().as_str(), port) {
         ("leader", 8091) => required_env("IGGY_TCP_ADDRESS_LEADER"),
         ("follower", 8092) => required_env("IGGY_TCP_ADDRESS_FOLLOWER"),
         ("single", 8090) | (_, 8090) => required_env("IGGY_TCP_ADDRESS"),
         _ => panic!("no address mapping for role '{role}' on port {port}"),
    }
}

fn required_env(name: &str) -> String {
    match env::var(name) {
        Ok(value) if !value.is_empty() => value,
        _ => panic!("{name} must be set; run the suite via scripts/run-bdd-tests.sh"),
    }
}

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Can be a good first issue