fix: prevent subdomain-only route from overwriting hostname route

[jalexiscv]

Description

Fixes #7214 - Inconsistent hostname/subdomain limitation in Routing

Problem

When using hostname and subdomain route options, the precedence was inconsistent depending on whether they were on the same route or separate routes:

Case 1: Same route (hostname took precedence - correct)

$routes->get('/', 'Home::index');
$routes->get('/', 'Media::index', ['hostname' => 'media.example.com', 'subdomain' => '*']);

media.example.com → Media::index ✓

Case 2: Separate routes (subdomain incorrectly won)

$routes->get('/', 'Home::index');
$routes->get('/', 'Media::index', ['hostname' => 'media.example.com']);
$routes->get('/', 'All::index', ['subdomain' => '*']);

media.example.com → All::index ✗ (should be Media::index)

Root Cause

Two issues:

1. elseif meant routes with both hostname and subdomain only validated hostname
2. No protection against subdomain-only routes overwriting hostname routes

Solution

1. Change elseif to if — both hostname and subdomain are validated independently
2. Track matchedByHostname/matchedBySubdomain flags during registration
3. Add guard: routes matched only by subdomain cannot overwrite existing hostname routes

Changes

One file: system/Router/RouteCollection.php

• Independent hostname/subdomain validation
• Hostname route protection from subdomain-only overwrite

Ref: #7214
Closes #7214

[mergeable]

Hi there, jalexiscv! 👋

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[paulbalandan]

Please add tests to prove the fix works. Also, add the fix to the changelog.