docs: add CHANGELOG.md for v0.1.0

Initial OSS release notes covering Phase 1 + Phase 2 OSS launch, detector-
assisted runtime integration, and the rules engine surface.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

Author: dchiitmalla

CHANGELOG.md

@@ -0,0 +1,34 @@
+# Changelog
+
+All notable changes to this project will be documented in this file.
+
+The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/),
+and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
+
+## [0.1.0] — 2026-05-12
+
+Initial open-source release of ProofLayer's runtime rules layer.
+
+### Added
+
+- **Detection engine** — 45 YAML rules across four attack categories (command injection, prompt injection, jailbreaks, data exfiltration), plus inline heuristics for Shannon entropy and semantic-mismatch checks.
+- **Runtime wrapping** — `ProofLayerRuntime` wraps MCP servers and intercepts `call_tool` invocations.
+- **Risk scoring + actions** — 0-100 score with `ALLOW` / `WARN` / `BLOCK` / `KILL` thresholds (configurable).
+- **MCP Python SDK support** via `pip install -e ".[mcp]"`.
+- **HTTP proxy mode** — `prooflayer proxy` inspects JSON-RPC `tools/call` traffic and forwards or rejects per scoring.
+- **CLI** — `prooflayer scan`, `prooflayer proxy`, rule validation, report inspection, version commands.
+- **Optional detector-assisted scoring** — runtime can call a `prooflayer-detector` service over `/v1/detect` for model-backed scoring of ambiguous events. Rules-only mode is the default; runtime degrades to rules-only on detector failure (does not block traffic on detector unavailability).
+- **Reporting** — JSON and SARIF reports for blocked or high-risk calls.
+- **Input normalization** for encoded, nested, and obfuscated arguments.
+- **Configuration** via `prooflayer.yaml` (detection thresholds, response actions, detector integration, logging).
+- **Examples** — `examples/basic/` (simple wrapped server), `examples/attack-scenarios/` (command injection, data exfiltration, prompt injection, jailbreak attempts), `examples/suse/` (SUSE Multi-Linux Manager integration with systemd service + config).
+- **Docker support** — `Dockerfile` and `docker-compose.yml`.
+- **Test suite** — 246 tests covering adversarial inputs, fuzz-like random inputs, end-to-end integration, and detector-client behavior.
+- **OSS project hygiene** — Apache-2.0 LICENSE, SECURITY.md (responsible disclosure to `founders@sinewaveai.com`), CODE_OF_CONDUCT.md (Contributor Covenant v2.1), CONTRIBUTING.md.
+
+### Notes
+
+- This is the initial OSS release. Public API is alpha — minor versions may introduce breaking changes until 1.0.
+- The commercial ML scoring tier (`prooflayer-detector`) is a separate offering; this repo is the open rules-only layer plus optional client for that service.
+
+[0.1.0]: https://github.com/sinewaveai/prooflayer-rules/releases/tag/v0.1.0