[QA] Explorer | Loading screen hangs silently with no user-facing error when connecting to a non-loopback local scene dev realm over http

### 🛠️ **Build version:**
Reproduces on both:
- `v0.169.0-alpha-bugsweep/aug16-consolidated-22a1a3d` (PR #9765, commit `22a1a3d`)
- `v0.169.0-alpha-main` (current production build, via standard launcher)

### 📔 **Issue Description:**
When launching Explorer pointed at a local scene dev server on a non-loopback LAN IP over http (e.g. `http://192.168.68.127:8000`), the client shows a "you are about to enter a custom catalyst" prompt, then the loading screen hangs indefinitely with no further feedback or error message to the user. This reproduces identically on **both** the PR #9765 build and the current production build (`v0.169.0-alpha-main`) — confirming it's a pre-existing gap, not something introduced by the bugsweep PR. The underlying blocking mechanism differs by build (see notes below), but in both cases the user is left staring at a frozen loading screen with zero explanation.

### 👣 **STR:**

1. Start a local SDK7 scene server (`npm run start`) so it's reachable on the machine's LAN IP (not just loopback)
2. Launch Explorer with: `open ./Decentraland.app --args --realm http://:8000 --position 0,0 --local-scene true --debug --scene-console --login-bridge-only`
3. Accept the "custom catalyst" prompt and wait on the loading screen

### ✔️ **Expected Result:**
Either the app clearly communicates that the connection was blocked/rejected (e.g. an "insecure connection not allowed" message or similar), or it fails fast with an actionable error — not an indefinite silent hang.

### ❌ **Actual Result with evidence:**
Loading screen hangs with no error shown to the user. All test sessions were manually force-quit after ~19-21 seconds of no progress.

**On PR #9765 build**, Player.log shows during asset bundle fetch attempts:
```
Curl error 35: Cert verify failed. Certificate could not be verified (either omitted or unsupported). UnityTls error code: 7
```
Occurred 3x per session, across two separate test attempts, immediately preceding manual app quit. Consistent with the new app-level cleartext-scheme enforcement (`wearable-mainfile-insecure-url` lane, `EnforceSecureScheme`) upgrading the non-loopback http request to https, then failing TLS handshake since the local dev server has no cert. (Inferred from the TLS failure signature — no `EnforceSecureScheme`/`insecure`/`cleartext` string is directly logged.)

**On production build (`v0.169.0-alpha-main`)**, Player.log shows instead:
```
Non-secure network connections disabled in Player Settings
```
Same silent hang, same lack of any in-app user messaging — this time it's Unity's engine-level `insecureHttpOption` (still `NotAllowed` on production) hard-blocking the connection outright.

In both cases, the connection is correctly prevented from silently succeeding over cleartext — **not a security bug**. The bug is purely the missing user-facing feedback: nothing tells the user why the loading screen is stuck or what to do about it.

### ➗ **Reproduction:**
##### 🔁 Always - (3/3 attempts: 2x on PR #9765 build, 1x on production build, same silent-hang result every time)

### 🖥️ **Operative system and additional Notes:**
macOS — Apple M3 Pro.

Confirmed pre-existing — reproduces on current production (`v0.169.0-alpha-main`) as well as the PR #9765 build, so this is **not a regression introduced by the bugsweep PR** and does not block that PR's merge. Filing as its own item since it's a real UX gap: likely a good candidate to fix as part of the local-scene-development / Creator Hub preview flow specifically, since that's the workflow most likely to hit a non-loopback address in practice.

[Player test 1 - wearable-mainfle.log](https://github.com/user-attachments/files/31185160/Player.test.1.-.wearable-mainfle.log)

[Player.log](https://github.com/user-attachments/files/31185162/Player.log)