Do not use version based on git (#87)

### What change is being made

Switch entirely from dynamic to fixed versioning in `pyproject.toml`.

### Why this change is being made

As this repository is synced, there is not a single source of truth for
versioning based on git, leading eventually to failures from the
pixi.lock.

### Tested

Ensured that 0.1.0 is applied in the `pixi.lock`.

GitOrigin-RevId: a2b322c117eee60e5993ff9a19f8f148c4cec062

Author: awoll-bdai

pixi.lock

@@ -4,8 +4,7 @@ description = "EXport and dePLOY Reinforcement Learning policies."
 name = "exploy"
 requires-python = ">=3.11"
 
-# Version is determined dynamically from git tags.
-dynamic = ["version"]
+version = "0.1.0"
 
 authors = [
     { name = "Dario Bellicoso", email = "dbellicoso@rai-inst.com" },
@@ -74,17 +73,7 @@ Tracker = "https://github.com/bdaiinstitute/exploy/issues"
 
 [build-system]
 build-backend = "hatchling.build"
-requires = ["hatchling", "hatch-vcs"]
-
-[tool.hatch.version]
-source = "vcs"
-
-[tool.hatch.version.raw-options]
-version_scheme = "only-version"
-local_scheme = "no-local-version"
-
-[tool.hatch.build.hooks.vcs]
-version-file = "python/exploy/_version.py"
+requires = ["hatchling"]
 
 [tool.hatch.build.targets.sdist]
 packages = ["python/exploy"]

pyproject.toml

@@ -1,6 +1,7 @@
 # Copyright (c) 2026 Robotics and AI Institute LLC dba RAI Institute. All rights reserved.
-from ._version import __version__
+from importlib.metadata import PackageNotFoundError, version
 
-__all__ = [
-    "__version__",
-]
+try:
+    __version__ = version(__name__)
+except PackageNotFoundError:
+    __version__ = "unknown"