refactor(web-app-mediawiki): unify debug & oidc handling via _ensure_require, introduce host-side prep, switch to bind mounts

- Removed obsolete Installation.md, TODO.md, 02_debug.yml, 05_oidc.yml and legacy debug enable/disable tasks
- Added 01_prep.yml to render debug.php/oidc.php on host side before container start
- Introduced _ensure_require.yml for generic require_once management in LocalSettings.php
- Renamed 01_install.yml -> 02_install.yml to align with new numbering
- Updated docker-compose.yml.j2 to bind-mount mw-local into /opt/mw-local
- Adjusted vars/main.yml to define MEDIAWIKI_LOCAL_MOUNT_DIR and MEDIAWIKI_LOCAL_PATH
- Templates debug.php.j2 and oidc.php.j2 now gated by MODE_DEBUG and MEDIAWIKI_OIDC_ENABLED
- main.yml now orchestrates prep, install, debug, extensions, oidc require, admin consistently

Ref: https://chatgpt.com/share/68b57db2-efcc-800f-a733-aca952298437

roles/web-app-mediawiki/templates/oidc.php.j2

@@ -1,18 +1,19 @@
 <?php
 // ### OIDC (PluggableAuth) – BEGIN (managed by Ansible)
+
+{% if MEDIAWIKI_OIDC_ENABLED | bool %}
+
 wfLoadExtension( 'PluggableAuth' );
 wfLoadExtension( 'OpenIDConnect' );
 
-$wgPluggableAuth_EnableAutoLogin = true;   // don’t auto-redirect to IdP
-$wgPluggableAuth_EnableLocalLogin = false;   // keep local user/pass login
+$wgPluggableAuth_EnableAutoLogin = true;
+$wgPluggableAuth_EnableLocalLogin = false;
 $wgPluggableAuth_ButtonLabel = '{{ MEDIAWIKI_OIDC_BUTTON_TEXT }}';
 
-// PluggableAuth expects a list of providers (numeric array) on REL1_44
 $wgPluggableAuth_Config = [
     [
         'plugin' => 'OpenIDConnect',
         'data' => [
-            // For Keycloak, use the REALM URL, e.g. https://auth.example/realms/<realm>
             'providerURL'  => '{{ MEDIAWIKI_OIDC_ISSUER }}',
             'clientID'     => '{{ MEDIAWIKI_OIDC_CLIENT_ID }}',
             'clientsecret' => '{{ MEDIAWIKI_OIDC_CLIENT_SECRET }}',
@@ -21,7 +22,8 @@ $wgPluggableAuth_Config = [
     ],
 ];
 
-// Helpful defaults
 $wgOpenIDConnect_UseEmailNameAsUserName = true;
 $wgOpenIDConnect_MigrateUsers = true;
 // ### OIDC (PluggableAuth) – END
+
+{% endif %}