fix(cli): issues submissions --json reports empty success when GITTENSOR_MINER_PAT is unset

[michiot05]

Summary

gitt issues submissions --id N --json reports success: true, submission_count: 0 when GITTENSOR_MINER_PAT is not set — even though the GitHub lookup never ran.

#1554 (for #1492) made the GraphQL lookup-failure path an explicit error instead of a silent empty success. The missing-token path still falls through to the same false negative, and only in the mode aimed at automation:

• fetch_open_issue_pull_requests (gittensor/cli/issue_commands/helpers.py:264) prints the "No GitHub token found" warning only when not as_json — JSON mode gets no signal
• it then calls find_prs_for_issue(..., token=None), which returns [] by design for a falsy token (documented as the precondition-not-met case, distinct from the None failure sentinel — that contract is unchanged here)
• back in submissions.py, only None is special-cased, so the [] flows into success: true, submission_count: 0

Production scenario: monitoring/automation runs gitt issues submissions --id N --json in an environment without GITTENSOR_MINER_PAT (read-only setups that never posted a PAT). It concludes the bounty issue has no open submissions when in reality nothing was looked up. Human mode at least prints a warning; --json mode is completely silent.

Fix: in JSON mode, a missing token now raises click.UsageError, which the existing handler maps to the canonical error envelope (error.type: "usage_error") with exit 1. This mirrors gitt miner post --json, which already refuses to run without a PAT ("required for JSON mode", miner_commands/post.py:93). Human mode is untouched (warn and continue). find_prs_for_issue's documented falsy-token → [] contract is untouched.

Related Issues

Completes the false-negative elimination started in #1554 (#1492) for the remaining silent path.

Type of Change

• Bug fix
• New feature
• Refactor
• Documentation
• Other (describe below)

Before / After

Reproduced with the contract reads stubbed and GITTENSOR_MINER_PAT unset; the GitHub-lookup CLI path is real.

Before — lookup never ran, reported as a successful empty result:

$ gitt issues submissions --id 42 --json   # GITTENSOR_MINER_PAT unset
{
  "success": true,
  "issue_id": 42,
  "repository": "entrius/gittensor",
  "issue_number": 223,
  "submission_count": 0,
  "submissions": []
}

(exit code: 0)

After — explicit error envelope, non-zero exit:

$ gitt issues submissions --id 42 --json   # GITTENSOR_MINER_PAT unset
{"success": false, "error": {"type": "usage_error", "message": "No GitHub token found; set GITTENSOR_MINER_PAT to fetch GitHub issue submissions"}}

(exit code: 1)

Human mode (no --json) is unchanged: prints the existing "No GitHub token found; set GITTENSOR_MINER_PAT..." warning and continues to "No open submissions available", exit 0. With a token set, both modes behave exactly as before.

Testing

• Tests added/updated
• Manually tested

Two tests added in tests/cli/test_issue_submission.py: JSON mode with the env var unset → success: false, error.type == "usage_error", non-zero exit; human mode with the env var unset → warning preserved, exit 0. Full suite: uv run pytest — 962 passed; uv run pre-commit run --all-files --hook-stage pre-push (ruff, pyright, vulture, pytest) — all green.

Checklist

• Code follows project style guidelines
• Self-review completed
• Changes are documented (if applicable)