chore: initialize repo with comprehensive .gitignore and README skeleton

Establishes the FabledRulebook-required ignore patterns (docs/superpowers/specs,
docs/superpowers/plans) plus Python/Node/Vite/extension/volumes/IDE rules from
spec §6.1 before any other code lands, so accidental adds can't leak. Also
ignores .claude/settings.local.json (per-user local overrides; shared
.claude/settings.json may be committed in the future).

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

.gitignore

@@ -0,0 +1,67 @@
+# FabledRulebook-required (agent-authored specs/plans live local only)
+docs/superpowers/specs/
+docs/superpowers/plans/
+
+# Secrets and environment
+.env
+.env.*
+!.env.example
+*.secret
+*.key
+*.pem
+
+# Python
+__pycache__/
+*.py[cod]
+*$py.class
+.pytest_cache/
+.mypy_cache/
+.ruff_cache/
+.coverage
+.coverage.*
+htmlcov/
+.tox/
+*.egg-info/
+build/
+dist/
+venv/
+.venv/
+
+# Node / Vue / Vite
+frontend/node_modules/
+frontend/dist/
+frontend/.vite/
+frontend/coverage/
+*.log
+npm-debug.log*
+yarn-debug.log*
+yarn-error.log*
+.pnpm-debug.log
+
+# Firefox extension build artifacts (lands in FC-3)
+extension/*.xpi
+extension/web-ext-artifacts/
+
+# Runtime volumes (must never be tracked)
+images/
+import/
+downloads/
+models/
+postgres_data/
+redis_data/
+
+# IDE / OS
+.vscode/
+.idea/
+*.swp
+*.swo
+.DS_Store
+Thumbs.db
+
+# Claude Code per-user local overrides (shared .claude/settings.json is OK to commit)
+.claude/settings.local.json
+
+# Alembic / DB scratch
+alembic/versions/__pycache__/
+*.sqlite
+*.sqlite-journal