diff --git a/.editorconfig b/.editorconfig
new file mode 100644
index 0000000..779f99a
--- /dev/null
+++ b/.editorconfig
@@ -0,0 +1,12 @@
+root = true
+
+[*]
+indent_style = space
+indent_size = 4
+end_of_line = lf
+charset = utf-8
+trim_trailing_whitespace = true
+insert_final_newline = true
+
+[*.md]
+trim_trailing_whitespace = false
diff --git a/.gitattributes b/.gitattributes
index 04c6eb9..8ddbd04 100644
--- a/.gitattributes
+++ b/.gitattributes
@@ -1,10 +1,25 @@
-# Keep packaged tarballs (Packagist downloads) small by stripping dev-only files
-/.github              export-ignore
-/.gitattributes       export-ignore
-/.gitignore           export-ignore
-/.php-cs-fixer.php    export-ignore
-/.phpstan.dist.neon   export-ignore
-/.rector.php          export-ignore
+# Keep Packagist/Composer downloads small: strip every file a consumer of the
+# package never runs. `git archive` (which is what GitHub and Packagist serve)
+# ignores a path that does not exist, so one canonical list works for every
+# module and library.
+/.claude                     export-ignore
+/.editorconfig               export-ignore
+/.gitattributes              export-ignore
+/.github                     export-ignore
+/.gitignore                  export-ignore
+/.idea                       export-ignore
+/.junie                      export-ignore
+/.mcp.json                   export-ignore
+/.php-cs-fixer.php           export-ignore
+/.phpstan.dist.baseline.neon export-ignore
+/.phpstan.dist.neon          export-ignore
+/AGENTS.md                   export-ignore
+/CLAUDE.md                   export-ignore
+/composer.lock               export-ignore
+/phpstan-baseline.neon       export-ignore
+/phpunit.xml                 export-ignore
+/rector.php                  export-ignore
+/tests                       export-ignore
 
 # Enforce LF line endings on checkout so the line-endings CI gate never fails
 *.css   text eol=lf
diff --git a/.github/workflows/lint.yml b/.github/workflows/lint.yml
index 11287a7..c37387c 100644
--- a/.github/workflows/lint.yml
+++ b/.github/workflows/lint.yml
@@ -15,7 +15,7 @@ jobs:
 
             - uses: shivammathur/setup-php@f3e473d116dcccaddc5834248c87452386958240  # 2.37.2
               with:
-                  php-version: '8.3'
+                  php-version: '8.5'
 
             - name: Install dependencies
               run: composer install --no-interaction --no-progress
@@ -24,4 +24,4 @@ jobs:
               run: php vendor/bin/php-cs-fixer fix --diff --dry-run
 
             - name: Rector
-              run: php vendor/bin/rector -c .rector.php --dry-run
+              run: php vendor/bin/rector --dry-run
diff --git a/.github/workflows/phpstan.yml b/.github/workflows/phpstan.yml
index 7190103..25b276a 100644
--- a/.github/workflows/phpstan.yml
+++ b/.github/workflows/phpstan.yml
@@ -12,7 +12,7 @@ jobs:
 
         strategy:
             matrix:
-                php-version: ['8.3', '8.4', '8.5']
+                php-version: ['8.5', '8.6']
 
         name: PHPStan (PHP ${{ matrix.php-version }})
 
diff --git a/.github/workflows/syntax-php.yml b/.github/workflows/syntax-php.yml
index 0010e57..eea74bb 100644
--- a/.github/workflows/syntax-php.yml
+++ b/.github/workflows/syntax-php.yml
@@ -13,7 +13,7 @@ jobs:
         strategy:
             fail-fast: false
             matrix:
-                php-version: ['8.3', '8.4', '8.5']
+                php-version: ['8.5', '8.6']
 
         name: PHP Syntax (PHP ${{ matrix.php-version }})
 
diff --git a/.php-cs-fixer.php b/.php-cs-fixer.php
index 53d5172..70dfa83 100644
--- a/.php-cs-fixer.php
+++ b/.php-cs-fixer.php
@@ -34,7 +34,8 @@
                 __DIR__ . '/src',
             ], 'is_dir')))
             // Root-level entry points (e.g. the infra tool's sync.php / config.php).
-            // glob skips dotfiles, so these very config files aren't included.
+            // glob skips dotfiles, so .php-cs-fixer.php is left out; rector.php is
+            // a plain name now, so it is formatted like any other file.
             ->append(glob(__DIR__ . '/*.php') ?: [])
             ->name('*.php')
             ->ignoreDotFiles(true)
diff --git a/composer.json b/composer.json
index 748f386..a266283 100644
--- a/composer.json
+++ b/composer.json
@@ -4,7 +4,7 @@
     "license": "OSL-3.0",
     "type": "maho-module",
     "require": {
-        "php": ">=8.3"
+        "php": ">=8.5"
     },
     "require-dev": {
         "friendsofphp/php-cs-fixer": "*",
@@ -20,7 +20,7 @@
             "mahocommerce/maho-composer-plugin": true
         },
         "platform": {
-            "php": "8.3"
+            "php": "8.5"
         }
     }
 }
diff --git a/.rector.php b/rector.php
similarity index 90%
rename from .rector.php
rename to rector.php
index 02c776c..8b848cb 100644
--- a/.rector.php
+++ b/rector.php
@@ -40,9 +40,10 @@ function gitUntrackedPaths(): array
             __DIR__ . '/lib',
             __DIR__ . '/public',
             __DIR__ . '/src',
-        ], 'is_dir'),
+        ], is_dir(...)),
         // Root-level entry points (e.g. the infra tool's sync.php / config.php).
-        // glob skips dotfiles, so this very config file isn't included.
+        // glob skips dotfiles, so .php-cs-fixer.php is left out; rector.php is
+        // a plain name now, so this config lints itself.
         glob(__DIR__ . '/*.php') ?: [],
     )))
     // No argument: Rector reads the target PHP version from composer.json
@@ -55,10 +56,10 @@ function gitUntrackedPaths(): array
     // package:
     //
     //  - AddTypeToConst emits `const string FOO`. That is new syntax, not a
-    //    rewrite, so a repo that declares no require.php floor (such as
-    //    maho-composer-plugin) would ship code its own metadata never promised.
-    //    A composer plugin also runs on the user's PHP, not on the platform the
-    //    project resolved against.
+    //    rewrite: it adds nothing the code needs, and it turns a floor bump into
+    //    a hard parse error for anyone who installs with platform requirements
+    //    ignored. A composer plugin also runs on the user's PHP, not on the
+    //    platform the project resolved against.
     //  - ReadOnlyClass / ReadOnlyProperty change the contract, not the code: a
     //    readonly class cannot be extended by a normal child, and a readonly
     //    property cannot be written from one. Maho modules exist to be extended.