Validate config keys against known set in config set

[smypmsa]

Problem

pumpfun config set rpcc https://... (typo) is silently stored. There is no validation against known config keys, so typos go unnoticed and the intended config never gets set.

Fix

Add validation in src/pumpfun_cli/commands/config.py config_set() against known keys:

KNOWN_KEYS = {"rpc", "keyfile", "priority_fee", "compute_units"}

if key not in KNOWN_KEYS:
    error(
        f"Unknown config key: {key}",
        hint=f"Valid keys: {', '.join(sorted(KNOWN_KEYS))}",
    )

Files to change

• src/pumpfun_cli/commands/config.py — add key validation
• tests/test_commands/test_config_cmd.py — add test for unknown key

How to test

uv run pytest tests/test_commands/test_config_cmd.py -v

[P-r-e-m-i-u-m]

"Hi @smypmsa, I'd like to work on this! I'll add the key validation and tests."

[smypmsa]

@P-r-e-m-i-u-m sure, you can try.