chore: import upstream snapshot with attribution

CONTRIBUTING.md

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+# Contributing to Gortex
+
+Thank you for considering contributing to Gortex! This guide will help you get started.
+
+## Licensing of contributions
+
+Gortex is released under the [Apache License, Version 2.0](LICENSE.md).
+By submitting a contribution (a pull request, patch, or other work) you
+agree that it is licensed to the project under the same Apache 2.0 terms,
+as described in section 5 of the License. You retain copyright in your
+contribution; the project retains a perpetual, worldwide, royalty-free
+license to use, modify, and redistribute it as part of Gortex.
+
+Contributors are listed in [CONTRIBUTORS.md](CONTRIBUTORS.md). Add yourself
+to that file in the same PR if you'd like to be credited.
+
+## Getting Started
+
+### Prerequisites
+
+- Go 1.21+
+- CGO enabled (required for tree-sitter C bindings)
+- Git
+
+### Building
+
+```bash
+git clone https://github.com/zzet/gortex.git
+cd gortex
+go build -o gortex ./cmd/gortex/
+```
+
+### Running Tests
+
+```bash
+go test -race ./...
+```
+
+### Running Benchmarks
+
+```bash
+go test -bench=. -benchmem ./internal/parser/languages/
+go test -bench=. -benchmem ./internal/query/
+go test -bench=. -benchmem ./internal/indexer/
+```
+
+## How to Contribute
+
+### Reporting Bugs
+
+- Open an issue with a clear description
+- Include the output of `gortex version` and `go version`
+- Provide a minimal reproduction if possible
+
+### Suggesting Features
+
+- Open an issue describing the feature and its use case
+- For language support requests, mention if the tree-sitter grammar is available in `github.com/smacker/go-tree-sitter`
+
+### Submitting Code
+
+1. Fork the repository
+2. Create a feature branch (`git checkout -b feature/my-feature`)
+3. Write tests for your changes
+4. Ensure all tests pass (`go test -race ./...`)
+5. Commit with a clear message
+6. Open a pull request
+
+### Adding a New Language Extractor
+
+This is one of the most impactful contributions. Follow these steps:
+
+1. Check if the tree-sitter grammar exists in `github.com/smacker/go-tree-sitter`
+2. Create `internal/parser/languages/<language>.go` implementing the `parser.Extractor` interface
+3. Create `internal/parser/languages/<language>_test.go` with at least 3 tests
+4. Register it in `internal/parser/languages/register.go`
+5. Debug the AST first — tree-sitter node types vary between grammars
+
+**What to extract (in priority order):**
+- Functions/methods with `EdgeMemberOf` to their class/type
+- Classes/types/interfaces
+- Interface method specs in `Meta["methods"]` (enables IMPLEMENTS inference)
+- Imports
+- Call sites
+- Variables/constants
+
+**Reference implementations:**
+- `golang.go` — the most complete extractor
+- `python.go` — simple OOP language
+- `rust.go` — systems language with impl blocks
+- `yaml.go` — simple config extractor
+
+### Code Style
+
+- Follow standard Go conventions (`gofmt`, `go vet`)
+- No unnecessary abstractions — three similar lines is better than a premature helper
+- Tests should be self-contained with inline source snippets
+- Extractor test helpers (`nodesOfKind`, `edgesOfKind`) are shared across test files
+
+## Project Structure
+
+```
+cmd/gortex/          CLI entry point and commands
+internal/
+  analysis/          Community detection, process discovery, impact analysis
+  claudemd/          CLAUDE.md generator
+  config/            Configuration loading
+  graph/             Core graph data structure (Node, Edge, Graph)
+  indexer/           Directory walker, file watcher
+  mcp/               MCP server and tool handlers
+  parser/            Extractor interface, tree-sitter helpers
+    languages/       Per-language extractors (one file each)
+  query/             Query engine (BFS traversal, SubGraph)
+  resolver/          Cross-file reference resolution, IMPLEMENTS inference
+  web/               Web visualization server (Sigma.js)
+pkg/gortex/          Public API for embedding
+```
+
+## Questions?
+
+Open an issue or start a discussion. We're happy to help!