Add battery dispatch implementation and Gitea CI pipeline

Implements the package from PLAN.md: config/data loading, the LP-first
MILP-fallback rolling-horizon optimiser, battery degradation tracking,
independent schedule validation, metrics, plots and the CLI, plus the
matching test suite. Adds a Gitea Actions workflow (lint + tests) that
posts a pass/fail notification to ntfy on every run, and a .gitignore
for build/cache artefacts that had been tracked by mistake.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

pyproject.toml

@@ -0,0 +1,38 @@
+[project]
+name = "battery-dispatch"
+version = "0.1.0"
+description = "Profit-maximising dispatch model for a 2 MW / 4 MWh battery across two wholesale electricity markets"
+readme = "README.md"
+requires-python = ">=3.11"
+dependencies = [
+    "pandas>=2.0",
+    "openpyxl>=3.1",
+    "pulp>=2.8",
+    "matplotlib>=3.8",
+]
+
+[project.optional-dependencies]
+dev = ["pytest>=8.0", "ruff>=0.6"]
+
+[project.scripts]
+battery-dispatch = "battery_dispatch.cli:main"
+
+[build-system]
+requires = ["hatchling"]
+build-backend = "hatchling.build"
+
+[tool.hatch.build.targets.wheel]
+packages = ["src/battery_dispatch"]
+
+[dependency-groups]
+dev = ["pytest>=8.0", "ruff>=0.6"]
+
+[tool.pytest.ini_options]
+testpaths = ["tests"]
+
+[tool.ruff]
+line-length = 100
+target-version = "py311"
+
+[tool.ruff.lint]
+select = ["E", "F"]