fix(cli): honor an explicit --wallet-name default in gitt issues register

[tryeverything24]

PR body — tryeverything24 → entrius/gittensor

Branch: fix/register-wallet-flag-resolution (commit c8a8257, in WSL /root/gtn-pr)

Base: test

Title: fix(cli): honor an explicit --wallet-name default in gitt issues register

Summary

gitt issues register resolves its wallet with a bare string comparison:

effective_wallet = wallet_name if wallet_name != 'default' else config.get('wallet', wallet_name)
effective_hotkey = wallet_hotkey if wallet_hotkey != 'default' else config.get('hotkey', wallet_hotkey)

An explicitly passed --wallet-name default (or --wallet-hotkey default) is
indistinguishable from "no flag given", so when ~/.gittensor/config.json names a different
wallet, the config value silently replaces the wallet the user asked for by name. Register is
the one command in this group that signs an owner-only on-chain transaction with the resolved
wallet's coldkey, so "loaded a different wallet than the one I typed" is the worst place
for this to happen.

The repo already has the correct resolver: resolve_wallet_config in
issue_commands/helpers.py is ParameterSource-aware (an explicit flag wins regardless of
its spelling) and gitt harvest — in this same file — already uses it. Register kept the
pre-helper heuristic.

Reproduction

Against origin/test @ 28c1d4c, with ~/.gittensor/config.json containing
{"wallet": "treasury-cold", "hotkey": "tk"} and all network/GitHub/contract I/O stubbed:

$ gitt issues register --repo o/r --issue 1 --bounty 10 --wallet-name default --hotkey default --yes ...
Loading wallet treasury-cold/tk...        # not the wallet named "default" that was requested

After the fix the same invocation loads default/default; omitting the flags still falls
back to treasury-cold/tk as documented.

Fix

Switch issue_register to the shared resolve_wallet_config (same call shape as harvest)
and drop the now-unused load_config() snapshot. Resolution priority is now genuinely
"explicit CLI flags > config file > defaults" for every spelling of the flags. The
local-network //Alice fallback still triggers on the same effective values as before —
no dev-workflow change.

Tests

New tests/cli/test_register_wallet_resolution.py (config written to a real temp file via a
redirected CONFIG_FILE, wallet construction captured through a stubbed bittensor.Wallet):

• test_explicit_default_flags_beat_config — --wallet-name default with a config wallet
  present loads default/default (fails on current test: loads the config wallet)
• test_config_fills_in_when_no_flags_given — config wallet/hotkey used when flags omitted
• test_explicit_named_wallet_beats_config — non-default explicit flags win
• test_defaults_used_when_no_flags_and_no_config — bare invocation resolves default/default

uv run pre-commit run --files gittensor/cli/issue_commands/mutations.py tests/cli/test_register_wallet_resolution.py   # all hooks Passed
uv run pyright                                                                                                         # 0 errors, 0 warnings
uv run vulture                                                                                                         # clean (exit 0)
uv run pytest tests/ -q                                                                                                # 964 passed

Note: open PR #1650 also touches issue_register, but only the confirmation-gate lines
(confirm_or_abort); this change is a different hunk (wallet resolution, ~15 lines below)
and merges cleanly in either order.