Adding documentation around building the project

Fixes #652
Modified the pyproject.toml removing the matrix from the default environment as the
matrix belongs on specific environments (like test) where multi-version behavior is
actually needed, not on the default environment which should be simple and
predictable.

Signed-off-by: Lalatendu Mohanty <lmohanty@redhat.com>

Author: LalatenduMohanty

docs/develop.md

@@ -30,4 +30,63 @@ writing to INFO level to show what is starting and stopping, respectively.
 Detailed messages should be logged to DEBUG level so they will not appear on the
 console by default.
 
+## Building the project
+
+The project uses [Hatch](https://hatch.pypa.io/) as its build system with [hatchling](https://hatch.pypa.io/latest/plugins/builder/wheel/) as the build backend. The build configuration is defined in `pyproject.toml`.
+
+### Development installation
+
+For development, you can install the project in editable mode:
+
+```bash
+# You can spawn a shell within an environment by using the hatch shell command.
+# It installs the project in editable/development mode.
+hatch shell
+
+# Check if fromager is installed and available in the path
+which fromager
+```
+Note: When a package is installed in editable/development mode, you can make changes to its source code directly. These changes are immediately reflected in your Python environment without needing to reinstall the package.
+
+### Quick build
+
+To build the project (both source distribution and wheel), use:
+
+```bash
+hatch build
+```
+
+This will create both `.tar.gz` (source distribution) and `.whl` (wheel) files in the `dist/` directory.
+
+You can build specific formats by using `hatch build -t wheel` or `hatch build -t sdist`.
+
+Alternatively, you can use the standard `build` module (which is included in the `[project.optional-dependencies.build]` section):
+
+```bash
+# Install build dependencies first
+pip install build twine
+
+# Build the project
+python -m build
+```
+
+### Package validation
+
+To validate the built packages, you can use the package linting script:
+
+```bash
+hatch run lint:pkglint
+```
+
+This command will:
+1. Build the project using `python -m build`
+2. Check the built packages with `twine check dist/*.tar.gz dist/*.whl`
+3. Validate Python version consistency between `pyproject.toml` and GitHub Actions workflows
+
+The validation will fail if:
+- The package metadata is malformed
+- Required files are missing from the distribution
+- Python version requirements are inconsistent across configuration files
+
+
 ### Building documentation

pyproject.toml

@@ -197,12 +197,12 @@ reportAttributeAccessIssue = false  # adding our own private property on click c
 # No specific python version here, so it uses the active Python by default.
 dependencies = []
 
-[[tool.hatch.envs.default.matrix]]
-python = ["3.11", "3.12", "3.13"]
-
 [tool.hatch.envs.test]
 features = ["test"]
 # {args:tests} allows passing arguments to specify which tests to run
+[[tool.hatch.envs.test.matrix]]
+python = ["3.11", "3.12", "3.13"]
+
 [tool.hatch.envs.test.scripts]
 test = "python -m coverage run -m pytest --log-level DEBUG -vv {args:tests}"
 coverage-report = ["coverage combine", "coverage report --format=markdown"]