[jm-rivera]

Rewrites the README for a public reader, adds a contributing guide and an MIT licence, and moves design notes into docs/development.md.

The repository had no LICENSE or CONTRIBUTING. LICENSE is now MIT, copyright ONE Campaign. CONTRIBUTING.md gives each package's CI commands (pytest, ruff, ty), the seven tools/validate_*.py validators and tools/tests, the registry mirror rule, the branch model and a changelog convention.

README.md replaced one dense status paragraph per package with a table of distribution, import name and purpose, and kept the uv, pip and [tool.uv.sources] install instructions, checked against each pyproject.toml. It drops references to a design document outside the repository and to planned freezes, and states the current fact that no package is on PyPI. The two schema families, the path-source dependency detail, and release and tag semantics move to docs/development.md.

CONTRIBUTING.md links the organisation code of conduct, security policy and support guide by absolute URL. Those links resolve once DevelopmentFinanceObservatory/.github#1 merges.

Left for a follow-up: schemas/spec/README.md and tools/README.md describe a drift check and codegen that do not exist, and the local v0.1.0 tag is not on origin, so the registry immutability check is skipped.

Testing: mdformat passes on the three files, the seven validators run clean, and tools/tests passes (53 tests). The package test suites were not run, since no code changed.