fix(cli): reject unknown keys in gitt config set to prevent silent typos

[plind-junior]

Summary

gitt config set KEY VALUE accepts any string for KEY and writes it to ~/.gittensor/config.json. Downstream commands look up settings by canonical name (config.get('wallet', 'default')), so a typo like wallet_name is silently dropped and the operator unknowingly continues with default values.

This PR whitelists KEY against the five settings that downstream commands actually read: wallet, hotkey, network, contract_address, ws_endpoint. Anything else is rejected at the CLI layer with a Click BadParameter error.

$ gitt config set wallet alice          # OK
Set wallet: alice

$ gitt config set wallet_name alice     # rejected
Usage: gitt config set [OPTIONS] {wallet|hotkey|network|contract_address|ws_endpoint} VALUE
Try 'gitt config set --help' for help.

Error: Invalid value for '{wallet|hotkey|...}': 'wallet_name' is not one of 'wallet', 'hotkey', 'network', 'contract_address', 'ws_endpoint'.

Why

Verified read-sites for the five canonical keys:

• wallet / hotkey — cli/miner_commands/check.py, post.py, cli/issue_commands/mutations.py
• network / ws_endpoint — cli/issue_commands/helpers.py:resolve_network, cli/miner_commands/helpers.py:_resolve_endpoint
• contract_address — used as the override for --contract flag

No reader consumes a key outside this list. Restricting writes to the same set is a safe, targeted fix.

Approach

Minimal-surface change: a single click.Choice on the existing positional KEY argument plus a key.lower() normalisation. The positional form (gitt config set wallet alice) is preserved — no breaking change for valid usages, no shell scripts to migrate. Only typo'd keys now fail.

If maintainers later want full btcli-style typed options (--wallet, --hotkey, …), CONFIG_KEYS is already the source of truth and the upgrade is incremental.

Changes

• gittensor/cli/main.py (+10 / −3): add CONFIG_KEYS constant; wrap the key arg in click.Choice(CONFIG_KEYS, case_sensitive=False); lowercase normalise; clarify docstring.
• tests/cli/test_config_set.py (new, +98): 10 tests covering valid keys (parametrised over all five), rejection of wallet_name, no-clobber-on-rejection guarantee, mixed-case normalisation, and the update-vs-set message branch.

Test plan

• pytest tests/cli/test_config_set.py -v — 10/10 pass
• pytest tests/cli/ — 117/117 pass (107 baseline + 10 new), no regressions
• Manual: gitt config set wallet alice → succeeds; gitt config set wallet_name alice → rejected with helpful error

Notes

• Backwards compatible for the documented usage pattern. Only previously-broken usages (typos that silently no-op'd) start failing — which is the intended behaviour.
• Doesn't conflict with adjacent in-flight PRs feat(cli): add gitt config get <key> subcommand #803 (config get, closed) or feat(cli): add gitt config unset <key> subcommand #804 (config unset, open). Both keep their own positional forms; if desired, they can adopt the same Choice pattern in a follow-up.

Fixes #812

[plind-junior]

@anderdc Fully ready for review