Add security workflow with composer audit, npm audit, and PHPStan

Adds a new GitHub Actions workflow that runs dependency vulnerability
checks for both PHP and Node packages, plus PHPStan static analysis
with Larastan. Includes a baseline for existing errors.

phpstan-baseline.neon

@@ -0,0 +1,67 @@
+parameters:
+	ignoreErrors:
+		-
+			message: '#^Access to an undefined property Illuminate\\Database\\Eloquent\\Model\:\:\$email\.$#'
+			identifier: property.notFound
+			count: 1
+			path: app/Jobs/SendApprovalDecisionEmail.php
+
+		-
+			message: '#^Cannot access property \$value on string\.$#'
+			identifier: property.nonObject
+			count: 1
+			path: app/Mail/ApprovalDecisionMail.php
+
+		-
+			message: '#^Result of && is always false\.$#'
+			identifier: booleanAnd.alwaysFalse
+			count: 2
+			path: app/Policies/TravelRequestPolicy.php
+
+		-
+			message: '#^Strict comparison using \=\=\= between string and App\\Enums\\TravelStatus\:\:Draft will always evaluate to false\.$#'
+			identifier: identical.alwaysFalse
+			count: 1
+			path: app/Policies/TravelRequestPolicy.php
+
+		-
+			message: '#^Strict comparison using \=\=\= between string and App\\Enums\\TravelStatus\:\:Pending will always evaluate to false\.$#'
+			identifier: identical.alwaysFalse
+			count: 1
+			path: app/Policies/TravelRequestPolicy.php
+
+		-
+			message: '#^Parameter \#1 \$action of method Filament\\Panel\:\:login\(\) expects array\<class\-string, string\>\|Closure\|string\|null, false given\.$#'
+			identifier: argument.type
+			count: 1
+			path: app/Providers/Filament/AdminPanelProvider.php
+
+		-
+			message: '#^Access to an undefined property Illuminate\\Database\\Eloquent\\Model\:\:\$id\.$#'
+			identifier: property.notFound
+			count: 1
+			path: app/Services/ApprovalService.php
+
+		-
+			message: '#^Access to an undefined property Illuminate\\Database\\Eloquent\\Model\:\:\$role\.$#'
+			identifier: property.notFound
+			count: 1
+			path: app/Services/ApprovalService.php
+
+		-
+			message: '#^Call to an undefined method Illuminate\\Database\\Eloquent\\Model\:\:steps\(\)\.$#'
+			identifier: method.notFound
+			count: 1
+			path: app/Services/ApprovalService.php
+
+		-
+			message: '#^Parameter \#1 \$travelRequest of job class App\\Jobs\\SendApprovalDecisionEmail constructor expects App\\Models\\TravelRequest in App\\Jobs\\SendApprovalDecisionEmail\:\:dispatch\(\), Illuminate\\Database\\Eloquent\\Model\|null given\.$#'
+			identifier: argument.type
+			count: 2
+			path: app/Services/ApprovalService.php
+
+		-
+			message: '#^Parameter \#1 \$travelRequest of job class App\\Jobs\\SendApprovalRequestEmail constructor expects App\\Models\\TravelRequest in App\\Jobs\\SendApprovalRequestEmail\:\:dispatch\(\), Illuminate\\Database\\Eloquent\\Model\|null given\.$#'
+			identifier: argument.type
+			count: 1
+			path: app/Services/ApprovalService.php