feat(server): add configurable SSH connection timeout per server

Add `connection_timeout` field to server settings, allowing per-server
override of the global SSH connection timeout constant.

- Migration adds `connection_timeout` integer column (default 10s)
- `ServerSetting` model exposes and casts the new field
- `SshMultiplexingHelper::getConnectionTimeout()` resolves per-server
  value with fallback to `constants.ssh.connection_timeout`
- All SSH/SCP command builders use the new resolver instead of the
  global config directly
- Livewire `Show` component binds `connectionTimeout` with validation
  (1–300 seconds) and syncs to/from the model
- UI input added to server settings form with helper text
- Feature tests cover default, persistence, resolver, and fallback

tests/Feature/ServerConnectionTimeoutTest.php

@@ -0,0 +1,43 @@
+<?php
+
+use App\Helpers\SshMultiplexingHelper;
+use App\Models\Server;
+use App\Models\User;
+use Illuminate\Foundation\Testing\RefreshDatabase;
+
+uses(RefreshDatabase::class);
+
+beforeEach(function () {
+    $user = User::factory()->create();
+    $this->team = $user->teams()->first();
+    $this->server = Server::factory()->create([
+        'team_id' => $this->team->id,
+    ]);
+});
+
+it('defaults connection_timeout to 10 seconds for new servers', function () {
+    expect($this->server->settings->connection_timeout)->toBe(10);
+});
+
+it('persists a custom connection_timeout value', function () {
+    $this->server->settings->connection_timeout = 30;
+    $this->server->settings->save();
+
+    expect($this->server->settings->fresh()->connection_timeout)->toBe(30);
+});
+
+it('returns the per-server connection_timeout from getConnectionTimeout', function () {
+    $this->server->settings->connection_timeout = 45;
+    $this->server->settings->save();
+
+    expect(SshMultiplexingHelper::getConnectionTimeout($this->server->fresh()))->toBe(45);
+});
+
+it('falls back to config default when connection_timeout is invalid', function () {
+    $this->server->settings->connection_timeout = 0;
+    $this->server->settings->saveQuietly();
+
+    $expected = (int) config('constants.ssh.connection_timeout');
+
+    expect(SshMultiplexingHelper::getConnectionTimeout($this->server->fresh()))->toBe($expected);
+});