TLS connections stall for 30+ seconds on cold start after Conscrypt Mainline update to 361331440 (Android 16)

## Description

After the Conscrypt Mainline module auto-updated to version `361331440` (delivered via Google Play System Update on April 5, 2026), all TLS connections stall for approximately 30 seconds on app cold start. The issue affects every HTTPS request — including simple HEAD requests to `connectivitycheck.gstatic.com` — ruling out any server-side cause.

The issue does **not** occur on a device with the older Conscrypt version `361153320`.

## Environment

**Affected device (reproduces):**
- Fairphone 6 (FP6), Android 16 (API 36)
- Build: `FP6.QREL.16.48.0`
- Security patch: 2026-02-05
- Conscrypt module: **361331440** (updated 2026-04-05)

**Control device (works fine):**
- Pixel 7 (panther), Android 16 (API 36)
- Build: `CP1A.260305.018`
- Security patch: 2026-03-05
- Conscrypt module: **361153320**

**App environment:**
- React Native 0.81.5 (Expo SDK 54)
- OkHttp (bundled with React Native)
- targetSdkVersion 36

## Steps to Reproduce

1. Have a device with Conscrypt version `361331440` (delivered via April 2026 Google Play System Update)
2. Cold-start the app
3. Observe that all HTTPS connections (fetch/OkHttp) fail or hang for ~10-15 up to 30 seconds before succeeding

## Evidence

### Affected device (Fairphone 6, Conscrypt 361331440)

Every probe — including HEAD requests to Google's own connectivity check endpoint — aborts after 5 seconds (JS-side timeout). The underlying tRPC fetch hangs for 30+ seconds before finally completing:

```
[boot-diag] === Boot diagnostics start === (+46ms)
[boot-diag] netinfo.initial: +233ms connected=true internetReachable=true type=wifi
[boot-diag] fetch: start https://api-staging.ovalbrief.com/trpc/presidents.list...

[boot-diag] probe[1].google: ERR Aborted 5020ms (+5066ms)
[boot-diag] probe[1].api: ERR Aborted 5020ms (+5066ms)
[boot-diag] probe[2].google: ERR Aborted 5024ms (+7082ms)
[boot-diag] probe[2].api: ERR Aborted 5024ms (+7082ms)
[boot-diag] probe[3].google: ERR Aborted 5023ms (+9087ms)
... (all 15 probes abort identically)
[boot-diag] probe[15].google: ERR Aborted 5027ms (+33152ms)
[boot-diag] probe[15].api: ERR Aborted 5027ms (+33152ms)

[boot-diag] fetch: done status=200 +63834ms ...presidents.list ← 64 seconds!
[boot-diag] fetch: done status=200 +32215ms ...orders.list ← 32 seconds!
```

## What We've Ruled Out

| Theory | Evidence | Status |
|--------|----------|--------|
| Server-side issue | google.com HEAD requests also fail | ❌ Ruled out |
| OkHttp configuration | Custom OkHttpClientFactory with 15s connect timeout: no change | ❌ Ruled out |
| HTTP/2 multiplexing | Forced HTTP/1.1 via `protocols(listOf(Protocol.HTTP_1_1))`: no change | ❌ Ruled out |
| App code regression | No code changes; issue appeared after Conscrypt auto-update | ❌ Ruled out |
| Android OS update | OS build unchanged since Feb; only Conscrypt Mainline module updated April 5 | ❌ Ruled out |
| WiFi/network issue | NetInfo reports connected + internetReachable=true; Chrome works fine on same WiFi | ❌ Ruled out |
| DNS resolution | Both IP-based and domain-based requests fail identically | ❌ Ruled out |

## Key Observations

1. **NetInfo (Android ConnectivityManager) reports the network is fully connected and internet-reachable** during the entire stall period. The OS network stack is functional.

2. **expo-updates (which uses its own native HTTP client, not OkHttp)** successfully downloaded and applied an OTA update *during* the hang. This confirms the stall is specific to the TLS path used by OkHttp/Conscrypt, not the entire network stack.

3. **The ntfy app** (29.7k GitHub stars) reports an identical issue on Android 16: OkHttp stuck in CONNECTING state while HTTP polling works fine. See: https://github.com/binwiederhier/ntfy/issues/1634

4. The stall duration is consistently ~30 seconds, suggesting a hardcoded timeout or retry interval somewhere in the TLS handshake path.

## Cross-App Verification

Tested other apps on the affected Fairphone 6 (Conscrypt `361331440`):

- **Coinbase** (React Native, standard OkHttp): **hangs on cold start** — same behavior as our app
- **Discord** (React Native, custom native networking layer): works fine — consistent with this being an OkHttp/Conscrypt interaction, not a general Android networking issue

This confirms the issue affects any app using OkHttp's default TLS path through Conscrypt, not just our app.

## Impact

This affects any Android app using OkHttp (including all React Native apps) on devices that received the Conscrypt `361331440` update. Cold starts are delayed by 30-60+ seconds, making apps appear completely broken to users.

## Expected Behavior

TLS connections should establish within normal timeframes (< 1 second on WiFi) on cold start, as they do with Conscrypt version `361153320`.