change cloud feature flags to be loaded dynamically at runtime rather than set in build (#6246)

## Summary

Implements server-side remote configuration to decouple runtime behavior
from build artifacts, enabling dynamic configuration updates without
redeployment.

## Technical Changes

- **Replaced** build-time constants (`__MIXPANEL_TOKEN__`,
`__BUILD_FLAGS__`) with runtime configuration loaded from
`/api/features`
- Configuration now sourced from `window.__CONFIG__` (hydrated from
`/api/features` endpoint)
- **Added** `src/platform/remoteConfig/` service that polls server
configuration every 30 seconds
- **Modified** application bootstrap sequence in `main.ts` to load
remote config before module initialization (required for cloud builds)
- **Removed** global constants: `__BUILD_FLAGS__`, `__MIXPANEL_TOKEN__`.
Runtime subscription enforcement toggle via `subscription_required` flag
- Server health alerts with variant-based severity rendering
(info/warning/error) via topbar badges

## Rationale

- **Build-once-deploy-anywhere**: Single immutable artifact promoted
through environments (staging → production)
- **Zero-downtime configuration**: Update behavior without rebuilding or
redeploying the application
- **Incident response**: Disable features or display alerts dynamically
in response to outages or degraded service
- **Instant rollback**: Revert configuration changes server-side without
artifact redeployment
- **Progressive delivery**: Enable A/B testing, canary releases, and
user/region-based configuration
- **Environment parity**: Eliminate configuration drift between staging
and production builds
- Decouples deployment cadence from configuration changes
- Enables GitOps workflows for configuration management separate from
code deployments
- Supports real-time operational control of client behavior
- Reduces build matrix complexity (no per-environment builds)

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-6246-change-cloud-feature-flags-to-be-loaded-dynamically-at-runtime-rather-than-set-in-build-2966d73d3650811cbb41c9093961037a)
by [Unito](https://www.unito.io)

src/platform/telemetry/providers/cloud/MixpanelTelemetryProvider.ts

@@ -7,6 +7,8 @@ import { useWorkflowTemplatesStore } from '@/platform/workflow/templates/reposit
 import type {
   AuthMetadata,
   ExecutionContext,
+  ExecutionErrorMetadata,
+  ExecutionSuccessMetadata,
   RunButtonProperties,
   SurveyResponses,
   TelemetryEventName,
@@ -40,7 +42,7 @@ export class MixpanelTelemetryProvider implements TelemetryProvider {
   private isInitialized = false
 
   constructor() {
-    const token = __MIXPANEL_TOKEN__
+    const token = window.__CONFIG__?.mixpanel_token
 
     if (token) {
       try {
@@ -74,7 +76,7 @@ export class MixpanelTelemetryProvider implements TelemetryProvider {
         this.isEnabled = false
       }
     } else {
-      console.warn('Mixpanel token not provided')
+      console.warn('Mixpanel token not provided in runtime config')
       this.isEnabled = false
     }
   }
@@ -178,7 +180,15 @@ export class MixpanelTelemetryProvider implements TelemetryProvider {
 
   trackWorkflowExecution(): void {
     const context = this.getExecutionContext()
-    this.trackEvent(TelemetryEvents.WORKFLOW_EXECUTION_STARTED, context)
+    this.trackEvent(TelemetryEvents.EXECUTION_START, context)
+  }
+
+  trackExecutionError(metadata: ExecutionErrorMetadata): void {
+    this.trackEvent(TelemetryEvents.EXECUTION_ERROR, metadata)
+  }
+
+  trackExecutionSuccess(metadata: ExecutionSuccessMetadata): void {
+    this.trackEvent(TelemetryEvents.EXECUTION_SUCCESS, metadata)
   }
 
   getExecutionContext(): ExecutionContext {