Upgrade PHPStan to 2.x and raise analysis level from 6 to 10

- Bump phpstan/phpstan ^2.0 and szepeviktor/phpstan-wordpress ^2.0
- Move the analysis level into phpstan.neon (single source) and raise it to 10
- Add Val, a runtime coercion helper that narrows untyped WordPress boundary
  values (wpdb rows, REST params, superglobals, options) with explicit checks
  instead of blind casts, plus unit tests
- Type value-object fromRow() params as stdClass (what wpdb returns) and map
  columns through Val so unexpected shapes degrade safely
- Use %i identifier placeholders for table names in all wpdb::prepare() calls
  so every query string is a literal and identifiers are escaped by WordPress;
  raises the minimum WordPress version to 6.2 where %i was introduced
- Guard wpdb::prepare() null result before wpdb::query() in updateTax()
- Fix nullable get_permalink()/strtotime() handling, list types at REST and
  capability call sites, dead null-coalescing on checked superglobals, and
  narrow get_users() results before mapping
- Register Val method names with the ValidatedSanitizedInput sniff so it
  validates the real sanitizer around each superglobal read
- Update repository unit tests for the %i placeholder arguments

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

phpcs.xml.dist

@@ -44,7 +44,32 @@
         </properties>
     </rule>
 
+    <!--
+        Val::* type-narrowing helpers (src/Val.php) wrap superglobal reads so
+        PHPStan level 10 sees a typed value, e.g.
+        `absint( Val::int( $_GET['id'] ?? 0 ) )`. The sniff walks wrapping
+        calls innermost-out and aborts at the first unrecognised function
+        name, so the Val method names must be registered for it to look past
+        them. Because they are static calls (`::`), the sniff never credits
+        them as sanitizers themselves — it skips them and still requires a
+        real sanitizing function around the read.
+    -->
+    <rule ref="WordPress.Security.ValidatedSanitizedInput">
+        <properties>
+            <property name="customUnslashingSanitizingFunctions" type="array">
+                <element value="int"/>
+                <element value="intOrNull"/>
+                <element value="float"/>
+                <element value="bool"/>
+            </property>
+            <property name="customSanitizingFunctions" type="array">
+                <element value="string"/>
+                <element value="stringOrNull"/>
+            </property>
+        </properties>
+    </rule>
+
     <!-- PHP 8.1+ minimum — allow modern syntax. -->
-    <config name="minimum_supported_wp_version" value="6.0"/>
+    <config name="minimum_supported_wp_version" value="6.2"/>
     <config name="testVersion" value="8.1-"/>
 </ruleset>