[jdjioe5-cpu]

What

Closes #2041.

Enhance --key in contract storage commands (read, restore, extend) so that it can parse more than just plain Symbol keys. --key now supports:

1. Valid Stellar StrKey addresses (G..., C..., M...), parsed into ScVal::Address
2. Standard XDR-JSON format representations (e.g., {"u64": 123456789})
3. JSON primitive/structured values (numbers, booleans, arrays, and objects)
4. Integer/boolean literals (e.g., 42, true)
5. Full backward compatibility: fallback to Symbol primitive parsing for existing plain string symbols

Why

Previously, --key was hardcoded to only accept ScSpecTypeDef::Symbol:

soroban_spec_tools::from_string_primitive(key, &xdr::ScSpecTypeDef::Symbol)?

This forced developers looking up storage entries keyed by addresses, integers, or complex values to either write manual scripts or use the base64-encoded --key-xdr option, which was inconvenient and unintuitive.

How

• Extracted and modularized key parsing into parse_key_arg(key_str: &str) -> Result<ScVal, Error>.
• Added address detection using stellar_strkey::Strkey.
• Added structured JSON conversion (json_to_scval) converting JSON numbers, booleans, arrays (ScVal::Vec), and maps (ScVal::Map).
• Retained seamless fallback to soroban_spec_tools::from_string_primitive(..., Symbol) preserving complete backward compatibility.
• Added comprehensive unit tests covering symbols, account addresses, contract addresses, numbers, booleans, JSON arrays, JSON objects, and XDR-JSON.