[Bug]: Chrome URL bar briefly flashes on cold start before fullscreen transition starting from Chrome 152

### Description
A Trusted Web Activity (TWA) application that previously launched directly into fullscreen mode without any visible browser UI now briefly flashes the Chrome URL bar / progress bar on cold start before transitioning into fullscreen.

The app, Digital Asset Links (`assetlinks.json`), and signing keys are completely unchanged. The regression is strictly tied to Chrome updates starting from Chrome 152 across Beta and Stable channels.

### Steps to Reproduce
1. Install the TWA app (`online.stellarspeak.www.twa`) on an Android device running Chrome 152 or 153.
2. Ensure the app is closed from Recent Apps (cold launch).
3. Tap the app icon from the system launcher.
4. Observe the launch sequence: the Chrome URL bar / top controls briefly appear for a fraction of a second, then hide automatically as the app enters fullscreen mode.
5. Downgrade Chrome to version 140.0.7339.207 or factory version 126.0.6478.71.
6. Launch the exact same, unchanged app build from the launcher: the app opens immediately into fullscreen mode with zero URL bar flash at any point.

### Expected Behavior
The application should open directly into fullscreen mode with no browser UI, URL bar, or navigation controls rendered during the startup transition.

### Actual Behavior
The Chrome URL bar / UI bar flashes briefly on launch before hiding itself and continuing in fullscreen mode.

### Environment & Test Details
- **App Package Name:** `online.stellarspeak.www.twa`
- **Origin:** `https://www.stellarspeak.online`
- **Asset Links URL:** `https://www.stellarspeak.online/.well-known/assetlinks.json`
- **Device Model:** 24116RACCG
- **Android Version:** 16

### Tested Chrome Versions
**Broken (Flash present on cold start):**
- Chrome Beta `152.0.7977.42`
- Chrome Stable `152.0.7977.64`
- Chrome Stable `152.0.7977.82`
- Chrome Beta `153.0.8010.36`

**Working (Direct fullscreen launch, no flash):**
- Chrome `140.0.7339.207`
- Chrome `126.0.6478.71`

### Additional Notes
- Digital Asset Links verification passes on every run (the app never falls back permanently to a standard Custom Tab).
- A/B/A testing with identical APK builds confirms the issue is tied directly to Chrome version updates.
- Is there any configuration in `android-browser-helper` (such as splash screen strategy, custom tab session parameters, or intent flags) that can suppress the toolbar rendering until verification completes and prevents this visual flash?

Start by reproducing the cold-start behavior with the listed Android device and Chrome 152/153 versions, then compare it with Chrome 140 and 126 using the unchanged app build. The issue names no repository file or test; done would require determining whether android-browser-helper configuration can prevent the toolbar flash or confirming that the regression is outside this library.

Written by the indexing model from the issue text.