Raises `phpstan.neon` level from 3 to 4 and fixes the 549 new errors
that level 4 surfaces across 157 files. Fixes are root-cause — no
`@phpstan-ignore`, no `@var` casts, no baseline entries, no widened
types. A handful of latent bugs were fixed along the way:
- `app/controllers/general.php`: path-traversal guard was negating
`\substr(...)` before the strict comparison (`!\substr(...) === $base`
was always `false === $base`). Rewritten as `\substr(...) !== $base`.
- `src/Appwrite/Platform/Modules/Databases/Http/Databases/Logs/XList.php`
and `.../TablesDB/Logs/XList.php`: were importing the raw Matomo
`DeviceDetector` (whose `getDevice()` returns `?int`) but treating the
result as an array with `deviceName/deviceBrand/deviceModel` keys.
Swapped to `Appwrite\Detector\Detector`, matching the wrapper already
used a few lines below for `$os`/`$client`.
- `src/Appwrite/Platform/Modules/Functions/Workers/Builds.php`: a match
key was checking `$resourceKey === 'functions'` when `$resourceKey`
is `'functionId'|'siteId'` — always false. Switched to the intended
`$resource->getCollection() === 'functions'` check.
- `src/Appwrite/OpenSSL/OpenSSL.php`: `encrypt()` return type tightened
to `string|false` to match `openssl_encrypt`; this lets callers'
`=== false` error handling remain meaningful.
- `app/controllers/api/messaging.php`: removed a dead
`array_key_exists('from', [])` branch in the Msg91 provider (empty
array literal; branch was unreachable).
Large cleanup categories across the 549 fixes:
- Removed redundant `?? default` on array offsets and expressions that
PHPStan now knows are non-nullable.
- Removed unreachable statements (mostly `return;` after `throw` or
`markTestSkipped()`).
- Removed redundant `is_array`/`is_string`/`is_bool`/`instanceof` checks
on already-narrowed types.
- Added `default =>` arms (or throwing arms) to non-exhaustive matches
on `string`/`mixed` input.
- Removed dead `$document === false` branches where method return types
were tightened to non-nullable `Document`.
- Removed unused properties (`$version` on Etsy/Zoom OAuth2, `$paths` on
Installer State, `$source` on MigrationsWorker, `$account2` on two
GraphQL auth tests), unused traits (`ApiVectorsDB`, `DatabaseFixture`),
and an unused `cleanupStaleExecutions` task method.
- Replaced `assertTrue(true)` and redundant `assertIsArray`/`assertIsString`/
`assertNotNull` assertions with `addToAssertionCount(1)` or
`assertNotEmpty` where the runtime type was already known.
