Add Family Connection and Context v1 conformance vectors

[fruwe]

Summary

• Add 152 machine-readable Family Connection/Context v1 conformance cases: 44 configuration, 67 endpoint, 15 environment-name, and 26 routing vectors.
• Preserve source-level JSON spellings for exact integer-version, duplicate-key, and non-finite numeric constant validation.
• Exercise canonical outputs and stable vector errors for the closed configuration model, routing precedence, injective environment names, strict URI handling, UTS #46 processing order, contextual joiner and bidi validation, Unicode 15.1 boundaries, Punycode, and DNS lengths.
• Use hash-pinned idna==3.7 Unicode 15.1 tables and RFC helpers while executing revision-31 ToASCII directly, without the package's additional IDNA2008 eligibility filter.
• Add a dedicated fixture-validation CI job without adding resolver behavior to any launcher package.

Scope boundary

This PR contains conformance fixtures and repository validation only. It does not implement networking, credential handling, a production resolver, launcher behavior, State behavior, protocol behavior, or client APIs. Python, Rust, and Node package source and package versions are unchanged.

Validation

• Validated head: 4e1ef53fbb0373a619f663f3a8764b6e60929f2c
• Official Unicode 15.1 IdnaMappingTable.txt and DerivedAge.txt checked for the pinned boundary vectors
• python/.venv/bin/pip install --require-hashes -r scripts/requirements-family-connection-v1-vectors.txt
• python/.venv/bin/python scripts/validate-family-connection-v1-vectors.py --verbose (152 passed)
• python/.venv/bin/ruff check scripts/validate-family-connection-v1-vectors.py
• Python launcher: ./.venv/bin/pip install -e '.[dev]', ./.venv/bin/ruff check ., ./.venv/bin/pytest -q (12 passed)
• Rust launcher: cargo build --release, cargo clippy --release --all-targets -- -D warnings, cargo test (8 passed)
• Node launcher: node test/dispatch.test.js
• Documentation local-link validation
• git diff --check
• GitHub Actions: family vectors, Python launcher, Rust launcher, and Node launcher passed

Closes #10