(fix): .env vars not available during runtime config reloads (healthchecks fail with MissingEnvVarError) (#12748)

* Config: reload dotenv before env substitution on runtime loads

* Test: isolate config env var regression from host state env

* fix: keep dotenv vars resolvable on runtime config reloads (#12748) (thanks @rodrigouroz)

---------

Co-authored-by: Tak Hoffman <781889+Takhoffman@users.noreply.github.com>

src/config/io.ts

@@ -4,6 +4,7 @@ import fs from "node:fs";
 import os from "node:os";
 import path from "node:path";
 import type { OpenClawConfig, ConfigFileSnapshot, LegacyConfigIssue } from "./types.js";
+import { loadDotEnv } from "../infra/dotenv.js";
 import { resolveRequiredHomeDir } from "../infra/home-dir.js";
 import {
   loadShellEnvFallback,
@@ -191,6 +192,15 @@ function normalizeDeps(overrides: ConfigIoDeps = {}): Required<ConfigIoDeps> {
   };
 }
 
+function maybeLoadDotEnvForConfig(env: NodeJS.ProcessEnv): void {
+  // Only hydrate dotenv for the real process env. Callers using injected env
+  // objects (tests/diagnostics) should stay isolated.
+  if (env !== process.env) {
+    return;
+  }
+  loadDotEnv({ quiet: true });
+}
+
 export function parseConfigJson5(
   raw: string,
   json5: { parse: (value: string) => unknown } = JSON5,
@@ -213,6 +223,7 @@ export function createConfigIO(overrides: ConfigIoDeps = {}) {
 
   function loadConfig(): OpenClawConfig {
     try {
+      maybeLoadDotEnvForConfig(deps.env);
       if (!deps.fs.existsSync(configPath)) {
         if (shouldEnableShellEnvFallback(deps.env) && !shouldDeferShellEnvFallback(deps.env)) {
           loadShellEnvFallback({
@@ -323,6 +334,7 @@ export function createConfigIO(overrides: ConfigIoDeps = {}) {
   }
 
   async function readConfigFileSnapshot(): Promise<ConfigFileSnapshot> {
+    maybeLoadDotEnvForConfig(deps.env);
     const exists = deps.fs.existsSync(configPath);
     if (!exists) {
       const hash = hashConfigRaw(null);