Prepare policy crate for publication to crates.io

[Copilot]

This PR prepares the policy crate for publication to crates.io, making it available as a standalone library for other projects to use.

Overview

The policy crate is a well-isolated component that provides parsing and validation for capability-based security policies for MCP servers. It has no dependencies on other crates in this repository and is ready to be shared with the broader Rust ecosystem.

Changes Made

Added Concise README.md (99 lines)

Created /crates/policy/README.md with essential documentation including:

• Overview and features - Clear explanation of what the crate does and its key capabilities
• Installation instructions - How to add the crate to a Cargo.toml
• Quick start guide - Code examples to get users started quickly
• Example policy YAML - Complete policy configuration example
• Features list - Core capabilities (storage, network, environment, resources, validation)
• API examples - Usage examples for PolicyParser and PolicyDocument
• Examples - Links to the testdata directory with real-world policy examples
• Cross-reference to policy-mcp - Highlighting the primary consumer of this crate
• Support links - GitHub Issues, Discussions, and Discord

Updated Cargo.toml Metadata

Added all required metadata for crates.io publication:

description = "A Rust library for parsing and validating capability-based security policies for MCP servers"
repository = "https://github.com/microsoft/wassette"
homepage = "https://github.com/microsoft/wassette"
readme = "README.md"
keywords = ["mcp", "security", "policy", "webassembly", "permissions"]
categories = ["parser-implementations", "web-programming", "config"]
authors = ["Microsoft Corporation"]

Note: The documentation field is omitted as docs.rs will automatically generate and host documentation when the crate is published.

Updated CHANGELOG.md

Added an entry to the Unreleased section documenting this preparation work.

Verification

All quality checks pass:

• ✅ cargo package - No warnings
• ✅ cargo test - All 40 unit tests + 5 doc tests pass
• ✅ cargo clippy - No linting issues
• ✅ cargo doc - Documentation builds successfully
• ✅ cargo publish --dry-run - Ready for publication
• ✅ Package includes README.md (99 lines) and all necessary files
• ✅ No local crate dependencies

Publishing

Once this PR is merged, a maintainer with crates.io credentials can publish the crate:

cd crates/policy
cargo publish

This will make the policy crate available at:

• crates.io: https://crates.io/crates/policy
• docs.rs: Documentation will be automatically generated and hosted

The crate can then be used by policy-mcp and other projects that need capability-based security policy management.

Original prompt

The policy crate is much decoupled from the rest of the codebase and does not depend on any other crates in this repo. Can you make sure that the policy crate is in a state where we can publish it to crates.io so that other projects can use this? Can you add a README to the policy crate that cross reference to https://github.com/microsoft/policy-mcp

---

💬 We'd love your input! Share your thoughts on Copilot coding agent in our 2 minute survey.

[Mossaka]

@copilot crates/policy/Cargo.toml:9 remove this

[Copilot]

@copilot crates/policy/Cargo.toml:9 remove this

Removed the documentation field from Cargo.toml in commit b8481c7.