Add project infrastructure and core application files

Add .gitignore, GitLab CI pipeline with test/lint/build/release stages, project documentation (README, LICENSE, CHANGELOG, CONTRIBUTING, SECURITY), PyInstaller packaging configuration with icon and version info, Python project configuration with dependencies, and complete application source including battery provider, device discovery, settings management, UI components, startup control, and comprehensive test suite

.gitlab-ci.yml

@@ -0,0 +1,48 @@
+stages:
+  - test
+  - lint
+  - build
+  - release
+
+default:
+  tags:
+    - windows
+  before_script:
+    - py -3.12 -m pip install --disable-pip-version-check -r requirements.txt
+
+test:
+  stage: test
+  script:
+    - py -3.12 -m pytest
+
+lint:
+  stage: lint
+  script:
+    - py -3.12 -m ruff check .
+
+build:
+  stage: build
+  needs: ["test", "lint"]
+  script:
+    - py -3.12 -m PyInstaller --clean --noconfirm packaging/pyinstaller.spec
+    - powershell -NoProfile -Command "$hash=(Get-FileHash dist/LogitechBatteryWidget.exe -Algorithm SHA256).Hash.ToLower(); \"$hash  LogitechBatteryWidget.exe\" | Set-Content -Encoding ascii dist/LogitechBatteryWidget.exe.sha256"
+  artifacts:
+    name: "LogitechBatteryWidget-$CI_COMMIT_SHORT_SHA"
+    paths:
+      - dist/LogitechBatteryWidget.exe
+      - dist/LogitechBatteryWidget.exe.sha256
+    expire_in: 30 days
+
+release:
+  stage: release
+  needs:
+    - job: build
+      artifacts: true
+  script:
+    - powershell -NoProfile -Command "Get-Content dist/LogitechBatteryWidget.exe.sha256"
+  artifacts:
+    paths:
+      - dist/LogitechBatteryWidget.exe
+      - dist/LogitechBatteryWidget.exe.sha256
+  rules:
+    - if: '$CI_COMMIT_TAG'