chore: bootstrap repo skeleton with sprint 0 plan

- .gitignore (Python, Node, RT/maldev hygiene, secrets)
- README.md (project framing, stack, conventions, status)
- CHANGELOG.md (team kickoff decisions Q1/Q2/Q3, T2/T3/T4, auth strategy)
- tasks/spec-decisions.md (D-001..D-007 arbitrations on top of frozen spec)
- tasks/todo.md (sprint 0 backlog: B0.* / F0.* / S0.* / R0.*)
- tasks/lessons.md (empty, populated as work progresses)
- backend/ frontend/ docs/ scaffolding

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

.gitignore

@@ -0,0 +1,64 @@
+# Secrets
+.env
+.env.local
+.env.*.local
+*.pem
+*.key
+
+# Python
+__pycache__/
+*.py[cod]
+*$py.class
+*.so
+.Python
+.venv/
+venv/
+env/
+.pytest_cache/
+.mypy_cache/
+.ruff_cache/
+.coverage
+htmlcov/
+*.egg-info/
+dist/
+build/
+
+# Node / Frontend
+node_modules/
+dist/
+build/
+.vite/
+coverage/
+.eslintcache
+playwright-report/
+test-results/
+
+# Build artifacts (RT/maldev hygiene)
+*.exe
+*.dll
+*.bin
+*.o
+*.obj
+*.pdb
+
+# IDE
+.vscode/
+.idea/
+*.swp
+*.swo
+.DS_Store
+
+# OS
+Thumbs.db
+
+# DB local
+*.sqlite
+*.sqlite3
+*.db
+
+# Logs
+*.log
+logs/
+
+# Docker
+.docker/