refactor(scenario): remove step type and simplify scheduler to exec-only

- remove StepType, type column, and type field from step entity and DTOs
- remove executeLoginStep, executeSignStep, executeExecStep from scheduler
- inline exec logic directly in executeStepRun; all steps run execCode
- remove AuthService, EnvironmentService, runEnvironments from scheduler
- remove type selector from CreateStepPage and EditStepPage
- remove type badge column from ScenarioDetailPage
- fix useEffect dependency arrays in RunDetailPage (FINAL, id, runId, polling)
- fix duplicate /snippets proxy key in vite.config.ts
- remove unused escapeHtml export from hljs.ts

client/src/pages/run/AllRunsPage.tsx

@@ -3,7 +3,14 @@ import { useNavigate } from 'react-router-dom';
 import { useTranslation } from 'react-i18next';
 import { runs } from '../../api';
 import type { ScenarioRun, ScenarioRunStep, ScenarioRunStatus } from '../../api';
-import { AutoRefreshIndicator, Badge, Table, Timestamp, UuidBadge, type TableColumn } from '../../ui';
+import {
+  AutoRefreshIndicator,
+  Badge,
+  Table,
+  Timestamp,
+  UuidBadge,
+  type TableColumn,
+} from '../../ui';
 import type { BadgeVariant } from '../../ui';
 import styles from '../Page.module.css';
 
@@ -37,6 +44,7 @@ export function AllRunsPage() {
   const pollRef = useRef<ReturnType<typeof setInterval> | null>(null);
 
   const load = () => {
+    setLoading(true);
     runs
       .listAll()
       .then((res) => {
@@ -48,7 +56,7 @@ export function AllRunsPage() {
   };
 
   useEffect(() => {
-    setLoading(true);
+    // eslint-disable-next-line react-hooks/set-state-in-effect
     load();
     pollRef.current = setInterval(load, 10_000);
     return () => {
@@ -77,9 +85,7 @@ export function AllRunsPage() {
       key: 'status',
       header: t('runs.col_status'),
       width: 110,
-      render: (r) => (
-        <Badge variant={STATUS_VARIANT[r.status]}>{STATUS_LABEL[r.status]}</Badge>
-      ),
+      render: (r) => <Badge variant={STATUS_VARIANT[r.status]}>{STATUS_LABEL[r.status]}</Badge>,
     },
     {
       key: 'steps',