Add CI, a pre-commit hook, and an accessibility pass on the panel's own views

CI (.github/workflows/tests.yml) reuses docker-compose.test.yml verbatim for
the Postgres job rather than re-describing that environment in YAML, so the
Docker image stays the single source of truth for it.

Fixes a real mismatch found while wiring PHP versions into the workflow:
composer.json declared "php": "^8.3", but the locked Symfony packages require
>=8.4.1 — installing on 8.3 would fail at `composer install`, exactly what
the Dockerfile's own comment already warned about. Bumped the constraint and
resynced composer.lock's content-hash (no package versions changed).

The pre-commit hook (.githooks/pre-commit, activated via
`git config core.hooksPath` in post-autoload-dump) runs `pint --dirty --test`
and refuses to commit unformatted files rather than silently rewriting them.

The accessibility pass only touches this app's own hand-written Blade views,
not Filament's components: aria-hidden on icons that repeat adjacent text,
an aria-label on the one icon that is the only signal of a health check's
severity, rel="noopener" and a labelled announcement on preview links that
open in a new tab.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

composer.lock

@@ -4,7 +4,7 @@
         "Read more about it at https://getcomposer.org/doc/01-basic-usage.md#installing-dependencies",
         "This file is @generated automatically"
     ],
-    "content-hash": "2c4a3ac0f2adf4cac823692240e8ca81",
+    "content-hash": "e9bbf5ad6f9f32f9f506caf56db81710",
     "packages": [
         {
             "name": "anourvalar/eloquent-serialize",
@@ -12591,7 +12591,7 @@
     "prefer-stable": true,
     "prefer-lowest": false,
     "platform": {
-        "php": "^8.3"
+        "php": "^8.4"
     },
     "platform-dev": {},
     "plugin-api-version": "2.6.0"