Implement Family Connection/Context v1 resolver across launchers

[fruwe]

Closes #12

Scope

• Add production Family Connection/Context v1 resolver APIs for Python, Rust, and Node.
• Parse and validate the closed configuration JSON model, including duplicate keys, exact numeric-token handling, and one Unicode scalar policy.
• Return opaque validated configuration objects, isolate them from caller mutation, and validate closed resolver requests without native exceptions or panics.
• Canonicalize endpoints according to the ordered v1 URI, UTS #46, IPv4, IPv6, port, path, and loopback HTTP profile.
• Encode injective environment override names and resolve named connections with exact precedence and no invalid-value fallthrough.
• Reserve config, context, and auth before product dispatch and omit reserved binaries from discovery, list, and help in all three launchers.

Review hardening

• Permit at most one dotted IPv4 production in IPv6 and only as the single final 32-bit component; focused Node tests cover compressed-left, compressed-right, and uncompressed multi-dotted forms.
• Use null-prototype Node parser and normalized objects so prototype-like source keys remain closed-model fields.
• Preserve arbitrary-precision Rust JSON number spelling so valid oversized numeric tokens reach invalid_version.
• Make the repository Rust vector runner separate from package-safe tests; repository instructions and CI execute it with cargo run, while an extracted crate passes cargo test --all-features.
• Pin the Rust toolchain action by immutable commit and pass stable/1.81.0 explicitly.
• Update the contract and deferred-work boundary to match implemented behavior.

Unicode and runtime support

• Python requires 3.11 or newer and pins idna==3.10 with unicodedata2==15.1.0.
• Node requires 22 or newer and pins tr46@5.0.0.
• Rust declares MSRV 1.81, pins behavior-relevant ICU data dependencies, and enables arbitrary-precision JSON token preservation.

Validation

• Shared reference vectors: 163 passed.
• Python: editable install, ruff check ., and pytest -q passed with 195 tests.
• Node: npm ci, npm test, and npm audit passed; audit found 0 vulnerabilities.
• Rust current: MSRV metadata check, locked release build, all-target/all-feature clippy with warnings denied, default/all-feature tests, and all 163 shared vectors passed.
• Rust 1.81.0: locked release build, default tests, and all 163 shared vectors passed.
• Published-crate simulation: cargo package --locked, extraction, and cargo test --locked --all-features passed using packaged contents only.
• git diff --check passed.

Excluded

• No networking, remote protocol/client, credential values or storage, configuration-file discovery, Determa State, protocol clients, package version bump, tag, or release.

Exact head: 4ce0d1dc39705fb0925bd1afcb3d99dd00ceb0b5.