feat: Change project license from AGPL to Apache 2.0

CONTRIBUTING.md

@@ -0,0 +1,67 @@
+# Contributing to Plotnik
+
+Thank you for your interest in contributing to Plotnik.
+
+## License Agreement
+
+By contributing to this project, you agree that your contributions will be licensed under the [Apache License 2.0](LICENSE).
+
+This means:
+- You grant a perpetual, worldwide, royalty-free patent license to all users
+- Your code can be used in commercial products without restriction
+- You retain copyright to your contributions
+
+## Before Contributing
+
+Read [`AGENTS.md`](AGENTS.md) — it's our constitution and contains:
+- Project ethos and design principles
+- Architecture Decision Records (ADRs)
+- Code and testing conventions
+- Project structure overview
+
+## Code Conventions
+
+### Style
+- Early returns over nested logic
+- Comments explain "why," not "what"
+- Code is written for senior engineers, not juniors
+
+### Testing
+- Tests live in `foo_tests.rs`, included via `#[cfg(test)] mod foo_tests;`
+- Use `insta` for snapshot testing
+- AAA pattern (Arrange-Act-Assert) separated by blank lines
+- Never write snapshots manually — use `@""` and `cargo insta accept`
+
+### Running Tests
+```sh
+make test              # Run all tests
+make snapshots         # Accept snapshot changes
+make coverage-lines    # Check coverage per file
+```
+
+### CLI Testing
+The `debug` command is your first testing tool:
+```sh
+cargo run -p plotnik-cli -- debug -q '(identifier) @id'
+cargo run -p plotnik-cli -- debug -q 'YourQuery' --only-symbols
+```
+
+## Submitting Changes
+
+1. **Fork and branch** — Create a feature branch from `main`
+2. **Write tests** — New features need tests, bug fixes need regression tests
+3. **Run checks** — Ensure `make test` passes
+4. **Keep commits atomic** — One logical change per commit
+5. **Write clear commit messages** — Explain the "why" behind the change
+6. **Submit a PR** — Reference any related issues
+
+## Architecture Changes
+
+If your contribution involves a significant architectural decision:
+- Create an ADR (Architecture Decision Record) in `docs/adr/`
+- Follow the template in `AGENTS.md`
+- Number it sequentially: `ADR-XXXX-short-title.md`
+
+## Questions?
+
+Open an issue for discussion before starting major work. We prefer to align on approach before you invest significant time.

README.md

@@ -18,7 +18,7 @@
   <a href="https://github.com/plotnik-lang/plotnik/actions/workflows/stable.yml"><img src="https://github.com/plotnik-lang/plotnik/actions/workflows/stable.yml/badge.svg" alt="stable"></a>
   <a href="https://github.com/plotnik-lang/plotnik/actions/workflows/nightly.yml"><img src="https://github.com/plotnik-lang/plotnik/actions/workflows/nightly.yml/badge.svg" alt="nightly"></a>
   <a href="https://codecov.io/gh/plotnik-lang/plotnik"><img src="https://codecov.io/gh/plotnik-lang/plotnik/graph/badge.svg?token=071HXJIY3E"/></a>
-  <a href="LICENSE.md"><img src="https://img.shields.io/badge/license-MIT-blue.svg" alt="MIT License"></a>
+  <a href="LICENSE"><img src="https://img.shields.io/badge/license-Apache--2.0-blue.svg" alt="Apache-2.0 License"></a>
 </p>
 
 <br/>
@@ -243,6 +243,6 @@ The CLI foundation exists. The full developer experience is ahead.
 
 ## License
 
-This project is licensed under the [AGPLv3].
+This project is licensed under the [Apache License (Version 2.0)].
 
-[AGPLv3]: LICENSE
+[Apache License (Version 2.0)]: LICENSE

crates/plotnik-cli/Cargo.toml

@@ -2,7 +2,7 @@
 name = "plotnik-cli"
 version = "0.1.0"
 edition = "2024"
-license = "AGPL-3.0-only"
+license = "Apache-2.0"
 description = "CLI for plotnik - typed query language for tree-sitter AST"
 repository = "https://github.com/plotnik-lang/plotnik"
 documentation = "https://docs.rs/plotnik-cli"

crates/plotnik-core/Cargo.toml

@@ -2,7 +2,7 @@
 name = "plotnik-core"
 version = "0.1.0"
 edition = "2024"
-license = "AGPL-3.0-only"
+license = "Apache-2.0"
 description = "Core data structures for Plotnik"
 repository = "https://github.com/plotnik-lang/plotnik"
 

crates/plotnik-langs/Cargo.toml

@@ -2,7 +2,7 @@
 name = "plotnik-langs"
 version = "0.1.0"
 edition = "2024"
-license = "AGPL-3.0-only"
+license = "Apache-2.0"
 description = "Tree-sitter language bindings for Plotnik query language"
 repository = "https://github.com/plotnik-lang/plotnik"
 documentation = "https://docs.rs/plotnik-langs"

crates/plotnik-lib/Cargo.toml

@@ -2,7 +2,7 @@
 name = "plotnik-lib"
 version = "0.1.0"
 edition = "2024"
-license = "AGPL-3.0-only"
+license = "Apache-2.0"
 description = "Typed query language for tree-sitter AST"
 repository = "https://github.com/plotnik-lang/plotnik"
 documentation = "https://docs.rs/plotnik-lib"

crates/plotnik-macros/Cargo.toml

@@ -2,7 +2,7 @@
 name = "plotnik-macros"
 version = "0.1.0"
 edition = "2024"
-license = "AGPL-3.0-only"
+license = "Apache-2.0"
 description = "Procedural macros for Plotnik"
 repository = "https://github.com/plotnik-lang/plotnik"