feat(json): add JSON command support

[bsbodden]

Implement all JSON commands with complete feature parity to redis-py:

• JSON.GET, JSON.SET, JSON.DEL, JSON.MGET, JSON.MSET
• JSON.ARRAPPEND, JSON.ARRINDEX, JSON.ARRINSERT, JSON.ARRLEN, JSON.ARRPOP, JSON.ARRTRIM
• JSON.OBJKEYS, JSON.OBJLEN, JSON.STRLEN, JSON.STRAPPEND
• JSON.NUMINCRBY, JSON.NUMMULTBY
• JSON.TOGGLE, JSON.CLEAR, JSON.TYPE
• JSON.RESP, JSON.DEBUG
• Support for both legacy (.) and modern ($) JSONPath syntax
• Add json_forget alias for json_del

Testing:

• Add 97 tests covering all commands
• All edge cases and error conditions tested
• JSONPath query tests for both syntaxes
• Array and object manipulation tests
• Numeric operation tests

Documentation:

• Add json_tutorial.rb example demonstrating all features
• Add search_with_json.rb example showing JSON with Search
• Include practical examples for common use cases

[byroot]

• None of the new methods are documented.
• The feature is only added to standalone redis, not to cluster or distributed.

[byroot]

I'm not sure how convenient that really is. If I'm working with a list of paths I received, and sometimes it is of length 1, sometimes more, I get inconsistent results.

Might be better to accept either a single path or an array, and return a consistent type.

[bsbodden]

Addressed:

1. Documentation: Added YARD docs to all methods (commit 6dd3596)

2. Distributed support: Implemented all JSON methods in Redis::Distributed using the node_for(key) delegation pattern. Multi-key operations (json_mget, json_mset) properly use ensure_same_node to enforce same-node requirements (commit 7e8906d)

3. Cluster support: Added test suite for Redis::Cluster. Since Cluster inherits from Redis, it automatically has access to all JSON commands without additional implementation (commit 1b1ef5c)

[bsbodden]

I'm not sure how convenient that really is. If I'm working with a list of paths I received, and sometimes it is of length 1, sometimes more, I get inconsistent results.

Might be better to accept either a single path or an array, and return a consistent type.

Yup. I've removed the unwrapping logic, see (commit 6dd3596).

The methods now always return the raw parsed JSON response from Redis without conditional unwrapping.

[byroot]

Suggested change

	parse_json(send_command(['JSON.ARRPOP', key, path, index.to_s]))
	parse_json(send_command(['JSON.ARRPOP', key, path, Integer(index).to_s]))

We should enforce the type of Integer arguments for consistency with the rest of the codebase (e.g. see linsert).

[bsbodden]

Fixed! Changed json_arrpop to use Integer(index) for proper type enforcement, see (commit 6dd3596).

[byroot]

As mentioned before, that helper is a smell. We should know what type to expect in return of the command we emit, instead of having a generic helper that can parse about anything.

[bsbodden]

The challenge with JSON commands is that Redis returns JSON-encoded strings that need parsing, and the return type varies by command and path query:

• json_get can return objects, arrays, strings, numbers, booleans, or null
• Array operations can return single values or arrays depending on JSONPath queries
• Some commands like json_arrpop return the actual JSON value, not metadata

I kept the helper with proper error handling (raises Redis::JSONParseError on parse failures) as it centralizes the JSON parsing logic and symbolize_names option. However, I'm open to refactoring this if you have a preferred pattern - perhaps individual parsing lambdas similar to Hashify/Floatify in Commands?

[byroot]

You just copy pasted all the tests for distributed. That's not how it should be done. Please look at the test/lint directory and how it defines modules (like Lint::Lists) that are shared between standalone and distributed redis.