[Rigidity]

Adds examples/json.rue, a JSON parser and serializer written in Rue, and links it from the README.

• Each kind of JSON value is a struct with a constant kind field, so a Json value can be narrowed with is.
• The parser handles every JSON escape, including \uXXXX with surrogate pairs (encoded as UTF-8). It also enforces JSON's rules on whitespace, leading zeros and control characters, and calls raise with a message when the input is malformed.
• stringify writes the value back as compact JSON, and get looks up keys in objects.
• Numbers must be integers, since CLVM has no fractions.

Rue string literals have no escape sequences, so the tests write JSON with single quotes and a json() helper swaps them for double quotes.

I also ran 13 malformed inputs through temporary tests (not committed), and each one failed with the expected error.

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Note

Low Risk
Documentation and example-only changes with snapshot YAML; no compiler, stdlib, or production puzzle logic is modified.

Overview
Adds examples/json.rue, a Rue example that parses JSON into tagged structs, serializes back to compact JSON, and exposes get for object lookup. main round-trips a string via stringify(parse(input)).

Parsing covers objects, arrays, literals, integer-only numbers (rejects . / e), escapes including \u and surrogate pairs (UTF-8), whitespace rules, and raise on malformed input. Tests use a json() helper (single quotes → double quotes) because Rue literals lack escapes.

Also adds the usual examples/json.yaml compile/test snapshot and links the example in the README.

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