feat: convert to pip package

- Restructure repo into hermes_identity_plugin/ Python package
- Add pyproject.toml with setuptools build config
- Register identity entry point under hermes_agent.plugins
- Include plugin.yaml, .json, .yaml as package data
- Update README with pip install instructions and project layout

pyproject.toml

@@ -0,0 +1,21 @@
+[build-system]
+requires = ["setuptools"]
+build-backend = "setuptools.build_meta"
+
+[project]
+name = "hermes-identity-plugin"
+version = "1.0.0"
+description = "Identity mapping plugin for Hermes Agent"
+authors = [{name = "@gortium"}]
+license = {text = "MIT"}
+requires-python = ">=3.11"
+dependencies = []
+
+[project.entry-points.'hermes_agent.plugins']
+identity = "hermes_identity_plugin:register"
+
+[tool.setuptools.packages.find]
+include = ["hermes_identity_plugin*", "docs*"]
+
+[tool.setuptools.package-data]
+"*" = ["*.json", "*.yaml"]