refactor: fix all 105 PHPStan 2 strict type findings across core and modules

Resolve all non-false-positive PHPStan 2 findings, reducing the baseline
from 486 to 382 entries (only unused-public false positives remain).

Categories fixed:
- Remove 39 redundant type checks (is_string, is_array, is_object, method_exists)
- Remove 12 no-op array_values() on already-sequential lists
- Simplify 13 null-coalesce on guaranteed offsets
- Remove 8 always-true instanceof checks
- Replace 12 redundant test assertions (assertTrue(true) → addToAssertionCount)
- Simplify 6 unnecessary nullsafe operators (?-> → ->)
- Fix 6 always-true !== '' comparisons
- Fix remaining: unset.offset, return.unusedType, staticMethod narrowing

53 files changed across core/, modules/, pages/, and tests/.

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

core/App/Module/ModuleRegistry.php

@@ -283,7 +283,7 @@ final class ModuleRegistry
 
         // — Merge search resources (fail-fast on duplicate provider) ——
         foreach ($manifest->searchResources as $provider) {
-            if (!is_string($provider) || trim($provider) === '') {
+            if (trim($provider) === '') {
                 throw new RuntimeException(
                     "Search resource provider in module '{$manifest->id}' must be a non-empty class-string."
                 );
@@ -333,7 +333,7 @@ final class ModuleRegistry
 
         // — Merge layout context providers ————————————————
         foreach ($manifest->layoutContextProviders as $providerClass) {
-            if (!is_string($providerClass) || trim($providerClass) === '') {
+            if (trim($providerClass) === '') {
                 throw new RuntimeException(
                     "Layout context provider in module '{$manifest->id}' must be a non-empty class-string."
                 );
@@ -343,7 +343,7 @@ final class ModuleRegistry
 
         // — Merge session providers ——————————————————————
         foreach ($manifest->sessionProviders as $providerClass) {
-            if (!is_string($providerClass) || trim($providerClass) === '') {
+            if (trim($providerClass) === '') {
                 throw new RuntimeException(
                     "Session provider in module '{$manifest->id}' must be a non-empty class-string."
                 );
@@ -353,7 +353,7 @@ final class ModuleRegistry
 
         // — Merge authorization policies (fail-fast on duplicate) ———
         foreach ($manifest->authorizationPolicies as $policyClass) {
-            if (!is_string($policyClass) || trim($policyClass) === '') {
+            if (trim($policyClass) === '') {
                 throw new RuntimeException(
                     "Authorization policy in module '{$manifest->id}' must be a non-empty class-string."
                 );
@@ -402,7 +402,7 @@ final class ModuleRegistry
                 'default_schedule_time' => $schedulerJob['default_schedule_time'],
                 'default_schedule_weekdays_csv' => $schedulerJob['default_schedule_weekdays_csv'],
                 'default_catchup_once' => (int) $schedulerJob['default_catchup_once'],
-                'allowed_schedule_types' => array_values($schedulerJob['allowed_schedule_types']),
+                'allowed_schedule_types' => $schedulerJob['allowed_schedule_types'],
                 'module_id' => $manifest->id,
             ];
         }
@@ -637,10 +637,10 @@ final class ModuleRegistry
     /** @return list<string> */
     public function getPermissionKeys(): array
     {
-        return array_values(array_map(
+        return array_map(
             static fn (array $permission): string => (string) $permission['key'],
             $this->mergedPermissions
-        ));
+        );
     }
 
     /** @return list<class-string> */