feat: package skeleton

[blaspat]

Summary

Bootstrap hermes-nodes-plugin as a pip-installable package that auto-loads into Hermes via the hermes_agent.plugins entry-point group.

What's in this PR

• pyproject.toml: setuptools build, project metadata, dev extras (pytest, pytest-asyncio), hermes_agent.plugins entry point, setuptools package discovery, pytest config
• hermes_nodes_plugin/__init__.py: stub register(ctx) that no-ops; __version__ = 0.1.0
• tests/test_smoke.py: 4 tests covering import, register contract, idempotency, and entry-point discovery
• tests/__init__.py, .gitignore: standard Python project layout

Design decision (please review)

The plan said entry-point target should be hermes_nodes_plugin:register (module:function form). I diverged to hermes_nodes_plugin (module only) after simulating Hermes's loader:

# hermes_cli/plugins.py:_load_plugin
module = self._load_entrypoint_module(manifest)   # <-- ep.load()
register_fn = getattr(module, "register", None)
if register_fn is None:
    loaded.error = "no register() function"

ep.load() on a module:function target returns the function, not the module. Then getattr(function_obj, "register", None) is always None, so Hermes silently logs "no register() function" and the plugin never loads. The module-only form is what Hermes's own dev guide documents.

I added a regression-guard test that fails if anyone reverts to the module:function form. If you specifically want the module:function form, the fix has to happen in Hermes's loader (out of scope for this repo).

Verification

• pip install -e . succeeds in a fresh venv (3.11.15)
• pytest -v — 4/4 pass
• ruff check . — clean
• Static security scan — clean (no secrets, no shell injection, no eval/exec, no pickle, no SQL injection)
• Independent reviewer subagent — passed

Refs

• Plan: §Task 2.1
• Spec: REQUIREMENTS.md §FR-3

Test plan for reviewer

git clone https://github.com/blaspat/hermes-nodes-plugin.git
cd hermes-nodes-plugin
python -m venv .venv && source .venv/bin/activate
pip install -e ".[dev]"
pytest -v