feat: add PostHog telemetry provider for cloud builds

- Add posthog-js dependency
- Create PostHogTelemetryProvider following MixpanelTelemetryProvider pattern
- Register provider in initTelemetry.ts
- Read posthog_project_token and posthog_api_host from window.__CONFIG__ (runtime config from /features endpoint)
- Extract getExecutionContext to shared utility used by both Mixpanel and PostHog
- Add PostHog to dist telemetry scan and license clarifications
- Tree-shaken away in OSS builds (verified)

Author: robinjhuang

.github/license-clarifications.json

@@ -0,0 +1,3 @@
+{
+  "posthog-js@*": { "licenses": "Apache-2.0" }
+}

.github/workflows/ci-dist-telemetry-scan.yaml

@@ -79,3 +79,22 @@ jobs:
             exit 1
           fi
           echo '✅ No Mixpanel references found'
+
+      - name: Scan dist for PostHog telemetry references
+        run: |
+          set -euo pipefail
+          echo '🔍 Scanning for PostHog references...'
+          if rg --no-ignore -n \
+            -g '*.html' \
+            -g '*.js' \
+            -e '(?i)posthog\.init' \
+            -e '(?i)posthog\.capture' \
+            -e 'PostHogTelemetryProvider' \
+            -e 'ph\.comfy\.org' \
+            -e 'posthog-js' \
+            dist; then
+            echo '❌ ERROR: PostHog references found in dist assets!'
+            echo 'PostHog must be properly tree-shaken from OSS builds.'
+            exit 1
+          fi
+          echo '✅ No PostHog references found'

.github/workflows/ci-oss-assets-validation.yaml

@@ -100,6 +100,7 @@ jobs:
             --production \
             --summary \
             --excludePackages '@comfyorg/comfyui-frontend;@comfyorg/design-system;@comfyorg/registry-types;@comfyorg/shared-frontend-utils;@comfyorg/tailwind-utils;@comfyorg/comfyui-electron-types' \
+            --clarificationsFile .github/license-clarifications.json \
             --onlyAllow 'MIT;MIT*;Apache-2.0;BSD-2-Clause;BSD-3-Clause;ISC;0BSD;BlueOak-1.0.0;Python-2.0;CC0-1.0;Unlicense;(MIT OR Apache-2.0);(MIT OR GPL-3.0);(Apache-2.0 OR MIT);(MPL-2.0 OR Apache-2.0);CC-BY-4.0;CC-BY-3.0;GPL-3.0-only'; then
             echo ''
             echo '✅ All production dependency licenses are approved!'

global.d.ts

@@ -33,6 +33,8 @@ interface Window {
     gtm_container_id?: string
     ga_measurement_id?: string
     mixpanel_token?: string
+    posthog_project_token?: string
+    posthog_api_host?: string
     require_whitelist?: boolean
     subscription_required?: boolean
     max_upload_size?: number

package.json

@@ -100,6 +100,7 @@
     "loglevel": "^1.9.2",
     "marked": "^15.0.11",
     "pinia": "catalog:",
+    "posthog-js": "catalog:",
     "primeicons": "catalog:",
     "primevue": "catalog:",
     "reka-ui": "catalog:",