Polish open-source setup and documentation

[Spbd1]

Motivation

• Make the repository GitHub-ready by improving install/run/test ergonomics, adding practical docs, and providing a one-command developer experience.
• Provide a safe, local-first demo workflow with seeded demo inputs and a small benchmark so contributors can iterate on taxonomy and rules without a DB.
• Add containerization and environment guidance so users can run the MVP reproducibly in local or containerized environments.

Description

• Expanded the README and added practical documentation files (docs/*.md) that cover architecture, taxonomy design, taxonomy expansion protocol, annotation guidelines, evaluation protocol, API contract, dashboard user guide, limitations, and roadmap.
• Added container and runtime artifacts including Dockerfile, docker-compose.yml, and .env.example, plus a CHANGELOG.md and packaged startup improvements to keep the MVP database-free.
• Improved scripts and dev flow: enhanced scripts/dev.py to install deps, seed demo data, optionally import a taxonomy workbook, run backend and frontend, and open the browser; made scripts/run_backend.py env-configurable; added scripts/import_taxonomy_excel.py and scripts/export_taxonomy_excel.py fixes; and improved frontend dev server to accept host/port from args/env.
• Seeded practical demo and benchmark data (data/examples/demo_inputs.jsonl and data/benchmarks/mini_eval_set.jsonl), updated scripts/seed_demo_data.py to write artifacts only when missing, and applied small engine/pack fixes (import formatting, exporter attribute assignment, pack manager/importer tidy, and a reusable uvicorn stub for local startup/testing).

Testing

• Ran the test suite with make test (pytest): all tests passed (42 passed, 4 warnings).
• Ran lint/format checks with ruff: all checks passed after automatic fixes.
• Ran the evaluation harness with make evaluate / python scripts/run_evaluation.py: benchmark executed and produced metrics (precision/recall/F1 and error buckets) to serve as regression signals.
• Built the frontend with npm --prefix frontend run build and executed python scripts/dev.py --install to verify dependency installation and seeding; both commands completed successfully in this environment, while docker compose could not be exercised here because Docker is not available.

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Codex Task