Add .gitignore for Python build artifacts, venvs, and local state

The repository previously had no .gitignore, which meant local
__pycache__/, virtualenvs, pytest cache, coverage reports, log
files, SQLite databases under tests/.tmp/ and operator-local
incidentrelay.conf with secrets all showed up in git status and
risked being accidentally committed or copied into Docker images
via COPY . .

The ignore list covers:
- Python bytecode and import cache
- venv/, .venv/, env/, .env
- pytest, coverage and tests/.tmp/ artifacts
- runtime logs and SQLite databases
- local config files (incidentrelay.conf, *.local.conf)
- common IDE/editor and OS files
- packaging build/ and dist/ output

No tracked files are matched by the new patterns, so nothing
disappears silently from git status.

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

Author: megative

.gitignore

@@ -0,0 +1,40 @@
+# Byte-compiled / cache
+__pycache__/
+*.py[cod]
+*$py.class
+
+# Virtual environments
+venv/
+.venv/
+env/
+.env
+
+# Test artifacts
+.pytest_cache/
+.coverage
+.coverage.*
+htmlcov/
+tests/.tmp/
+
+# Local runtime data
+logs/
+*.log
+*.sqlite
+*.sqlite3
+*.db
+
+# Local config (operators put real secrets here)
+incidentrelay.conf
+*.local.conf
+
+# IDE / editor
+.idea/
+.vscode/
+*.swp
+*.swo
+.DS_Store
+
+# Build / packaging
+*.egg-info/
+build/
+dist/