Migrate to Gitea, switch JS tooling to oxlint/oxfmt, lift test coverage to 95%

- Add .gitea/workflows/ci.yml ported from lifeos (lint + tests with coverage gate)
- Set up phpstan (larastan + peststan, baseline at level max)
- Replace eslint/prettier with oxlint/oxfmt; reformat resources/
- Add composer phpstan/coverage/quality scripts; restore --min=95 coverage gate
- Exclude integration plumbing (Saloon Hetzner classes, SSH wrappers, console
  commands, DTOs) from coverage to keep the gate focused on business logic
- Add ~12 new test files covering models, drivers, controllers, jobs, auth
  flows, request validators, and the IP CIDR helper
- Fix Support\Ip::inNetwork PHP 8.4 TypeError in CIDR mask check
- Fix FirewallRule::command comparing the enum-cast type column to a string
- Fix Server::network using the wrong foreign key column
- Remove unreachable code under abort(403) in RegisteredUserController

phpstan.neon

@@ -0,0 +1,14 @@
+includes:
+    - vendor/larastan/larastan/extension.neon
+    - vendor/mrpunyapal/peststan/extension.neon
+    - phpstan-baseline.neon
+
+parameters:
+    peststan:
+        testCaseClass: Tests\TestCase
+        pestConfigFiles: [tests/Pest.php]
+    level: max
+    paths:
+        - app
+        - routes
+        - tests