Align the tooling with the ecosystem standard.

.gitattributes

@@ -2,9 +2,6 @@
 
 *.php text diff=php
 
-# Keep Claude tooling scripts out of GitHub's language statistics
-/.claude             export-ignore
-
 # Dev-only, excluded from the Packagist tarball
 /.github             export-ignore
 /docs                export-ignore

.github/copilot-instructions.md

@@ -0,0 +1,12 @@
+# Copilot instructions
+
+## Context
+
+PHP library in the tiny-blocks ecosystem.
+
+## Mandatory pre-task step
+
+Before starting any task, read and strictly follow `.claude/CLAUDE.md` and every rule file in
+`.claude/rules/`. These files are the absolute source of truth for code generation. Apply every
+rule strictly. Do not deviate from the patterns, folder structure, or naming conventions defined
+in them.

phpstan.neon.dist

@@ -3,26 +3,24 @@ parameters:
     paths:
         - src
         - tests
+    tmpDir: reports/phpstan
     ignoreErrors:
         # The bcmath stubs type every operand as numeric-string. The library validates the shape
         # before a value reaches a calculator, and the Calculator contract documents it, so the
         # narrowing cannot be expressed without PHPDoc, which is prohibited inside src/Internal/.
         - identifier: argument.type
           path: src/Internal/Backends/BcMathCalculator.php
-
         # PHPDoc is prohibited on concrete collaborators inside src/Internal/, so the working
         # lists inside the allocation algorithm are suppressed here rather than annotated.
         - identifier: argument.type
           path: src/Internal/Allocations/Allocation.php
         - identifier: missingType.iterableValue
           path: src/Internal/Allocations/Allocation.php
-
         # Schoolbook multiplication fills the product by computed index, so PHPStan cannot prove the
         # result is still a list. It is: every index from zero upward is written before it is read.
         - identifier: argument.type
           path: src/Internal/Backends/Magnitude.php
           count: 1
-
         # PHPDoc is prohibited inside tests/, so data provider return types are suppressed here
         # rather than annotated.
         - identifier: missingType.iterableValue