feat: add validation tooling and expand path review instructions

Add pre-commit hooks (YAML lint, schema validation, editorconfig),
CI workflow, and new path instructions for test files, Dockerfiles,
config files, and archival docs.

.editorconfig

@@ -0,0 +1,15 @@
+root = true
+
+[*]
+charset = utf-8
+end_of_line = lf
+insert_final_newline = true
+trim_trailing_whitespace = true
+indent_style = space
+indent_size = 2
+
+[*.md]
+trim_trailing_whitespace = false
+
+[Makefile]
+indent_style = tab

.github/workflows/validate.yml

@@ -0,0 +1,21 @@
+---
+name: Validate Configuration
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+    branches: [main]
+
+permissions:
+  contents: read
+
+jobs:
+  validate:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-python@v5
+        with:
+          python-version: '3.12'
+      - uses: pre-commit/action@v3.0.1

.gitignore

@@ -0,0 +1,6 @@
+# Python
+__pycache__/
+*.py[cod]
+
+# Pre-commit
+.pre-commit-cache/

.pre-commit-config.yaml

@@ -0,0 +1,35 @@
+---
+repos:
+  # Standard hooks: basic file hygiene
+  - repo: https://github.com/pre-commit/pre-commit-hooks
+    rev: v6.0.0
+    hooks:
+      - id: check-yaml
+        args: ['--allow-multiple-documents']
+      - id: end-of-file-fixer
+      - id: trailing-whitespace
+      - id: check-merge-conflict
+
+  # YAML linting
+  - repo: https://github.com/adrienverge/yamllint
+    rev: v1.38.0
+    hooks:
+      - id: yamllint
+        args: [--strict]
+
+  # JSON Schema validation against CodeRabbit's official schema
+  - repo: https://github.com/python-jsonschema/check-jsonschema
+    rev: 0.37.0
+    hooks:
+      - id: check-jsonschema
+        name: Validate coderabbit.yaml against schema
+        files: ^coderabbit\.yaml$
+        args:
+          - '--schemafile'
+          - 'https://storage.googleapis.com/coderabbit_public_assets/schema.v2.json'
+
+  # EditorConfig compliance
+  - repo: https://github.com/editorconfig-checker/editorconfig-checker.python
+    rev: '3.6.1'
+    hooks:
+      - id: editorconfig-checker

.yamllint.yaml

@@ -0,0 +1,13 @@
+---
+extends: default
+rules:
+  line-length:
+    max: 120
+    allow-non-breakable-words: true
+    allow-non-breakable-inline-mappings: true
+  truthy:
+    check-keys: false
+    allowed-values: ['true', 'false', 'on', 'off']
+  comments:
+    min-spaces-from-content: 1
+  document-start: enable

README.md

@@ -21,4 +21,3 @@ This way the repository is always using the latest configuration.
 - [YouTube Channel](https://www.youtube.com/@CodeRabbitAI) - Official YouTube channel with tutorials and updates.
 - [AI Code Reviewer Examples](https://www.coderabbit.ai/blog/how-to-use-an-ai-code-reviewer-on-github-in-4-examples) - Four practical examples of using CodeRabbit.
 - [OpenAPI Documentation](https://api.coderabbit.ai/api/swagger/) - Complete Swagger documentation for CodeRabbit's REST API endpoints.
-

coderabbit.yaml

@@ -68,15 +68,37 @@ reviews:
       instructions: >-
         When a project contains a `docs/` directory:
         1. Consider the files in the `docs/` directory tree the core/main/in-depth
-           documentation of the project. Also consider the 'docs/**.md' files the
+        documentation of the project. Also consider the 'docs/**.md' files the
-           second place to look for project documentation after the 'README.md' file.
+        second place to look for project documentation after the 'README.md' file.
         2. When reviewing the documentation files (e.g. `docs/**.md`),
-           they should additionally be linted with help from the tool `markdownlint`, pointing out any issues.
+        they should additionally be linted with help from the tool `markdownlint`, pointing out any issues.
         3. When reviewing the documentation files in `docs/` directory, they should
-           additionally be linted with help from the tool `languagetool`, pointing out any issues.
+        additionally be linted with help from the tool `languagetool`, pointing out any issues.
         4. Focus on grammar, spelling, and punctuation.
         5. Also consider readability and clarity of contents.
         6. Avoid gender-specific language and use the imperative form.
+    - path: "docs/plans/**"
+      instructions: >-
+        These are historical design and planning documents. They may contain
+        outdated information and do not reflect current implementation.
+        Do not enforce current coding standards or suggest updates to align
+        with current practices. Focus only on grammar, spelling, and
+        readability if changes are being reviewed.
+    - path: "**/*.{test,spec}.*"
+      instructions: >-
+        These are test files. Focus on test coverage completeness,
+        assertion quality, and avoiding flaky test patterns.
+        Some duplication in tests is acceptable for readability —
+        do not enforce DRY as aggressively as in production code.
+    - path: "**/Dockerfile*"
+      instructions: >-
+        Review Dockerfiles for security best practices (non-root user,
+        minimal base images, no secrets baked into layers), multi-stage
+        build opportunities, and layer caching efficiency.
+    - path: "**/*.{json,yaml,yml,toml}"
+      instructions: >-
+        Configuration files: verify valid structure, ensure no hardcoded
+        secrets or credentials, and check consistency with project conventions.
   abort_on_close: true
   disable_cache: false
   auto_review:
@@ -222,4 +244,3 @@ code_generation:
     path_instructions: []
   unit_tests:
     path_instructions: []
-