Add community-health files + Copilot code-review skill

.github/CODEOWNERS

@@ -0,0 +1 @@
+* @framinosona

.github/copilot-instructions.md

@@ -0,0 +1,120 @@
+# GitHub Copilot Instructions for Plugin.BaseTypeExtensions
+
+## Project Overview
+
+**Plugin.BaseTypeExtensions** is a collection of extension methods for .NET base types —
+strings, numerics, enums, collections, dates/times, comparables, reflection, and a handful of
+other primitives — aimed at productivity, type safety, and readability in modern .NET
+applications.
+
+**Key Features:**
+- Null-safe string operations and character manipulation
+- Generic numeric operations for all `INumber<T>` types (angles, percentages, clamping)
+- Enum flag manipulation, description retrieval, and general enum utilities
+- Dictionary/list/enumerable extensions, including synchronization-aware variants
+- `DateTime`/`DateOnly`/`TimeOnly`/`TimeSpan` utilities
+- Reflection and assembly helpers (type discovery, attribute scanning, embedded resources)
+- `IComparable<T>` extensions plus standalone `ComparableTools`/`NumericRangeTools` helpers
+- Smaller extensions for `Byte`, `Guid`, `Version`, `Uri`, `Stream`, `Task`, `TaskCompletionSource`,
+  `CancellationToken`, `SemaphoreSlim`, `Random`, `Exception`
+
+## Technology Stack
+
+- **Framework:** .NET 9.0 (SDK `9.0.305`, see `global.json`)
+- **Language:** C# (latest)
+- **Testing:** xUnit + FluentAssertions (v7.x — stays open source indefinitely per Directory.Packages.props comment)
+- **Package Management:** Central Package Management (`Directory.Packages.props`)
+- **CI/CD:** GitHub Actions
+- **Documentation:** DocFX (`Plugin.BaseTypeExtensions.Docs/`, published to GitHub Pages)
+
+## Project Structure
+
+```
+Plugin.BaseTypeExtensions/
+├── .github/
+│   ├── workflows/ci.yml
+│   └── copilot-instructions.md   # This file
+├── Plugin.BaseTypeExtensions/          # Main library — one file per extended type/category
+│   ├── StringExtensions.cs
+│   ├── NumericExtensions.cs / NumericRangeTools.cs
+│   ├── EnumExtensions.cs
+│   ├── DictionaryExtensions.cs / ListExtensions.cs / EnumerableExtensions.cs
+│   ├── ConcurrentDictionaryExtensions.cs / SemaphoreSlimExtensions.cs
+│   ├── DateTimeExtensions.cs / DateOnlyExtensions.cs / TimeOnlyExtensions.cs / TimeSpanExtensions.cs
+│   ├── ComparableExtensions.cs / ComparableTools.cs
+│   ├── ReflectionExtensions.cs / AssemblyExtensions.cs
+│   ├── ByteExtensions.cs / GuidExtensions.cs / VersionExtensions.cs / UriExtensions.cs / StreamExtensions.cs
+│   ├── TaskExtensions.cs / TaskCompletionSourceExtensions.cs / CancellationTokenExtensions.cs
+│   ├── RandomExtensions.cs / ExceptionExtensions.cs
+├── Plugin.BaseTypeExtensions.Tests/    # xUnit tests, one file per source file
+└── Plugin.BaseTypeExtensions.Docs/     # DocFX documentation site
+```
+
+## Development Setup
+
+### Prerequisites
+- .NET SDK 9.0.305 or later (see `global.json`)
+
+### Build Commands
+```bash
+dotnet restore Plugin.BaseTypeExtensions.slnx
+dotnet build Plugin.BaseTypeExtensions.slnx --configuration Release --no-restore
+dotnet test Plugin.BaseTypeExtensions.Tests/Plugin.BaseTypeExtensions.Tests.csproj --configuration Release --no-build
+```
+
+## Code Organization Patterns
+
+- **One file per extended type or tightly-related group** — `*Extensions.cs`, named after the
+  type it extends (e.g. `StringExtensions.cs`). Don't mix categories in one file.
+- **Generic numeric code uses `INumber<T>`** constraints instead of per-type overloads.
+- **Standalone helpers that don't read naturally as extension methods** (e.g. clamping across a
+  pair of bounds) live in `ComparableTools`/`NumericRangeTools` as static classes — keep that
+  separation rather than bolting them onto `ComparableExtensions`/`NumericExtensions`.
+
+## Coding Standards
+
+### Naming Conventions (enforced by `.editorconfig`)
+- Classes/structs/interfaces/methods/properties/constants: PascalCase
+- Private fields: `_camelCase`
+- Parameters/locals: camelCase
+
+### Style Guidelines
+- Line length: max 240 characters; indentation: 4 spaces; line endings: LF
+- Prefer `var` when the type is apparent
+- Braces always required, even for single-line statements
+- `System` usings first, separated from the rest
+
+### Documentation Requirements
+- XML docs (`<summary>`, `<param>`, `<returns>`, `<exception>`) required on all public APIs
+
+## Testing Guidelines
+
+- **Framework:** xUnit, assertions via FluentAssertions (v7.2.2, open-source)
+- **File naming:** `{ClassName}Tests.cs`, matching the source file
+- **Test naming:** `MethodName_Scenario_ExpectedBehavior`
+- Cover success paths, failure paths, and boundary conditions (null, empty, min/max values)
+- Use `[Theory]`/`[InlineData]` for multiple similar cases; keep tests independent of each other
+
+## Dependencies
+
+### Production
+- `Microsoft.Extensions.Logging.Abstractions` (10.0.11)
+### Development
+- `xunit` (2.9.3), `xunit.runner.visualstudio` (4.0.0), `FluentAssertions` (7.2.2)
+- `coverlet.collector` / `coverlet.msbuild` (10.0.1)
+- `Microsoft.NET.Test.Sdk` (18.9.0), `JetBrains.Annotations` (2025.2.0)
+- `Microsoft.CodeAnalysis.NetAnalyzers` (10.0.400), `Microsoft.SourceLink.GitHub` (10.0.201)
+
+(Versions drift via Dependabot — check `Directory.Packages.props` for current values rather than
+trusting this list long-term.)
+
+## CI/CD Pipeline
+
+`ci.yml` runs: version generation → build/test/package → publish test artifacts → DocFX build and
+deploy to GitHub Pages → publish to NuGet.org (on `main`) → tag & GitHub release.
+
+## Useful Resources
+
+- **Repository:** https://github.com/laerdal/Plugin.BaseTypeExtensions
+- **NuGet Package:** https://www.nuget.org/packages/Plugin.BaseTypeExtensions
+- **Documentation:** https://laerdal.github.io/Plugin.BaseTypeExtensions/

.github/pull_request_template.md

@@ -0,0 +1,50 @@
+## Summary
+
+Describe the change in 2-6 lines.
+
+## Why
+
+Explain the reason for this change.
+
+## Change Type
+
+- [ ] Feature
+- [ ] Bug fix
+- [ ] Refactor
+- [ ] Docs only
+- [ ] CI/build/tooling
+
+## Affected Areas
+
+- [ ] String / Numeric / Enum extensions
+- [ ] Collection extensions (Dictionary / List / Enumerable / ConcurrentDictionary)
+- [ ] Temporal extensions (DateTime / DateOnly / TimeOnly / TimeSpan)
+- [ ] Reflection / Assembly extensions
+- [ ] Comparison extensions
+- [ ] Tests
+- [ ] Docs
+
+## Behavior And Compatibility
+
+- [ ] Public API changed
+- [ ] Exception behavior changed
+- [ ] No externally visible behavior change
+
+If any box above is checked, describe impact:
+
+## Tests
+
+- [ ] Unit tests added/updated
+- [ ] Not applicable (explain)
+
+## Documentation
+
+- [ ] README feature list updated
+- [ ] XML docs added/updated
+- [ ] Not applicable (explain)
+
+## Checklist
+
+- [ ] Commit messages follow Conventional Commits (`type(scope): subject`)
+- [ ] CI passes
+- [ ] Change is scoped to one logical unit of work

.github/skills/code-review/SKILL.md

@@ -0,0 +1,36 @@
+---
+name: code-review
+description: Use for reviewing pull requests on Plugin.BaseTypeExtensions — checks file-per-category organization, generic numeric constraints, and null/boundary safety on new extension methods.
+---
+
+# Code Review — Plugin.BaseTypeExtensions
+
+## Checklist for new or changed extension methods
+
+- [ ] **One file per extended type/category**: a new extension method belongs in the
+      `*Extensions.cs` file named after the type it extends (e.g. a new `DateTime` helper goes in
+      `DateTimeExtensions.cs`, not bundled into an unrelated file). A PR mixing categories into
+      one file, or adding a same-named method to two files, is a real finding.
+- [ ] **Generic numeric code uses `INumber<T>`**: new numeric operations should use generic math
+      constraints rather than adding per-type overloads (`int`, `double`, `float`, ...) — flag
+      copy-pasted overloads as a sign the generic constraint was skipped.
+- [ ] **Null/boundary safety**: string, collection, and comparable extensions handle `null`
+      input explicitly (per this library's "null-safe" positioning) rather than throwing an
+      unhandled `NullReferenceException`.
+- [ ] **Standalone helpers stay standalone**: logic that doesn't read naturally as an extension
+      method (e.g. clamping across a pair of bounds) belongs in `ComparableTools`/
+      `NumericRangeTools` as static helpers — don't bolt it onto `ComparableExtensions`/
+      `NumericExtensions` as an awkward extension method just to keep the "everything is an
+      extension" pattern.
+- [ ] **XML docs**: new public members have accurate `<summary>`/`<param>`/`<returns>`/
+      `<exception>` docs.
+- [ ] **README feature list**: a new extension category should be reflected there.
+
+## What to flag as a real risk, not a nit
+
+- A new extension method that duplicates behavior already available in `System.Linq` or the
+  BCL without a clear reason (this library's value is filling *gaps*, not re-wrapping existing
+  APIs).
+- Breaking changes to existing extension method signatures — this is a published NuGet package
+  consumed by other repos in this org (e.g. `Plugin.ExceptionListeners`), so a signature change
+  is a semver-relevant, not a routine tweak.

CODE_OF_CONDUCT.md

@@ -0,0 +1,55 @@
+# Contributor Covenant Code of Conduct
+
+## Our Pledge
+
+We as members, contributors, and leaders pledge to make participation in our community a
+harassment-free experience for everyone, regardless of age, body size, visible or invisible
+disability, ethnicity, sex characteristics, gender identity and expression, level of experience,
+education, socio-economic status, nationality, personal appearance, race, religion, or sexual
+identity and orientation.
+
+We pledge to act and interact in ways that contribute to an open, welcoming, diverse, inclusive,
+and healthy community.
+
+## Our Standards
+
+Examples of behavior that contributes to a positive environment include:
+
+- Demonstrating empathy and kindness toward other people
+- Being respectful of differing opinions, viewpoints, and experiences
+- Giving and gracefully accepting constructive feedback
+- Accepting responsibility and apologizing to those affected by our mistakes, and learning from
+  the experience
+- Focusing on what is best not just for us as individuals, but for the overall community
+
+Examples of unacceptable behavior include:
+
+- The use of sexualized language or imagery, and sexual attention or advances of any kind
+- Trolling, insulting or derogatory comments, and personal or political attacks
+- Public or private harassment
+- Publishing others' private information, such as a physical or email address, without their
+  explicit permission
+- Other conduct which could reasonably be considered inappropriate in a professional setting
+
+## Enforcement Responsibilities
+
+Maintainers are responsible for clarifying and enforcing standards of acceptable behavior and
+will take appropriate and fair corrective action in response to any behavior deemed
+inappropriate, threatening, offensive, or harmful.
+
+## Scope
+
+This Code of Conduct applies within all community spaces for this project, and also applies when
+an individual is officially representing the project in public spaces.
+
+## Enforcement
+
+Instances of abusive, harassing, or otherwise unacceptable behavior may be reported to the
+maintainer, [@framinosona](https://github.com/framinosona), via the contact details listed on
+their GitHub profile. All complaints will be reviewed and investigated promptly and fairly.
+
+## Attribution
+
+This Code of Conduct is adapted from the [Contributor Covenant](https://www.contributor-covenant.org),
+version 2.1, available at
+https://www.contributor-covenant.org/version/2/1/code_of_conduct.html.

CONTRIBUTING.md

@@ -0,0 +1,35 @@
+# Contributing
+
+## Branching
+
+Work off a short-lived feature branch cut from `main`. Open a PR early and mark it as a Draft
+if it's still in progress.
+
+## Commit convention
+
+This repo uses [Conventional Commits](https://www.conventionalcommits.org/): `type(scope): subject`,
+imperative mood, <= 72 characters. Common types: `feat`, `fix`, `docs`, `style`, `refactor`,
+`perf`, `test`, `chore`. Scope is optional but recommended (e.g. the extension category touched).
+
+## Pull requests
+
+Fill out the PR template. Keep each PR scoped to one logical change. CI must pass before merge.
+
+## Code style
+
+Follow this repo's `.editorconfig`. Prefer clarity over cleverness; avoid unnecessary abstraction
+— this is a firm preference, not a suggestion. Keep each extension category in its own
+`*Extensions.cs` file named after the type it extends (e.g. `StringExtensions.cs`,
+`DateTimeExtensions.cs`) — don't mix categories in one file. See
+`.github/copilot-instructions.md` for the existing conventions.
+
+## Testing
+
+All new functionality needs xUnit tests in `Plugin.BaseTypeExtensions.Tests`, using
+FluentAssertions for assertions. Test both success and failure paths and boundary conditions
+(null, empty, min/max values).
+
+## Documentation
+
+Public APIs need XML doc comments (`<summary>`, `<param>`, `<returns>`, `<exception>`). If you
+add a new extension category, update the README's feature list too.

SECURITY.md

@@ -0,0 +1,13 @@
+# Security Policy
+
+## Reporting a Vulnerability
+
+Please report security vulnerabilities privately using
+[GitHub's private vulnerability reporting](https://docs.github.com/en/code-security/security-advisories/guidance-on-reporting-and-writing/privately-reporting-a-security-vulnerability)
+(Security tab → "Report a vulnerability") rather than opening a public issue.
+
+We'll acknowledge reports as soon as possible and coordinate disclosure once a fix is available.
+
+## Supported Versions
+
+Only the latest published release is actively supported.