Please address the comments from this code review:

## Individual Comments

### Comment 1
<location path="agent/go-service/pkg/pienv/pienv.go" line_range="161-162" />
<code_context>
+	})
+}
+
+// Get returns the global Env. Returns nil if Init has not been called.
+func Get() *Env {
+	return global
+}
</code_context>
<issue_to_address>
**suggestion (bug_risk):** `Get` and the accessors silently return zero values when `Init` was not called, which can mask configuration issues.

Because `Get()` may return `nil` and the helpers default to empty strings, calling them before `Init` will fail silently and can change behavior compared to the previous `os.Getenv` usage (e.g. `i18n.Init` will always fall back to `DefaultLang` if `pienv.Init` is missed). To avoid this, either make `Get()`/the helpers call `once.Do(Init)` so they’re safe without explicit initialization, or detect uninitialized access (log or panic) to surface configuration bugs early.

Suggested implementation:

```golang
 // Get returns the global Env.
 // It panics if Init has not been called to surface configuration issues early.
func Get() *Env {
	if global == nil {
		panic("pienv.Get called before pienv.Init; ensure Init is invoked during service startup")
	}
	return global
}

```

If there are helper functions like `String()`, `Int()`, etc. that previously assumed `Get()` could return `nil`, they now rely on this panic behavior to protect against uninitialized access and don’t need further modification. However, if any call sites were defensively checking `if env := Get(); env != nil { ... }`, those checks are now redundant and can be simplified, since `Get()` will never return `nil` after this change.
</issue_to_address>