Add PHPStan level-8 static analysis with composer analyse and lint scripts

PHPStan at level 8 (the strictest) is added as a dev dependency with a
phpstan.neon targeting the src/ directory. Two new composer scripts make
common quality tasks discoverable without reading docs: `composer analyse`
runs static analysis and `composer lint` checks PHP syntax across src/
and tests/. This catches type errors, dead code, and unsafe operations
before they reach CI.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: aymanrb

composer.json

@@ -46,9 +46,12 @@
     "psr/log": "^1.0.1 || ^2.0 || ^3.0"
   },
   "require-dev": {
-    "phpunit/phpunit": "^10.5"
+    "phpunit/phpunit": "^10.5",
+    "phpstan/phpstan": "^2.0"
   },
   "scripts": {
-    "test": "phpunit --configuration phpunit.xml"
+    "test": "phpunit --configuration phpunit.xml",
+    "analyse": "phpstan analyse --configuration phpstan.neon",
+    "lint": "find src tests -name '*.php' -print0 | xargs -0 php -l"
   }
 }

phpstan.neon

@@ -0,0 +1,4 @@
+parameters:
+    level: 8
+    paths:
+        - src