fix: passthrough --json/--jq/--template flags in all gh subcommands

[shadowofdoom]

Summary

• gh pr view --json fields failed with Unknown JSON field: "--json" because view_pr() treated --json as the PR identifier
• The v0.21.1 fix (fix: gh run view drops --log-failed, --log, --json flags #159) only covered gh run view via should_passthrough_run_view()
• This generalizes the fix with has_output_format_flags() and applies it to all handlers that hardcode --json: list_prs, view_pr, pr_status, list_issues, view_issue, list_runs, and run_repo
• Also fixes view_pr to handle omitted PR number (gh defaults to current branch)

Reproduction

rtk gh pr view --json number,title,state
# Before: Unknown JSON field: "--json"
# After: passes through to gh correctly

Test plan

• All 383 tests pass (5 new tests for has_output_format_flags)
• rtk gh pr view --json number,title,state passes through correctly
• rtk gh pr list still uses RTK's compressed output
• rtk gh pr view <number> still uses RTK's compressed output

🤖 Generated with Claude Code

[pszymkowiak]

Tested locally on the branch — LGTM, approve.

All 383 tests pass. Manual testing confirms:

• gh pr view --json, gh pr list --json --jq, gh issue list --json --jq, gh repo view --json, gh pr status --json, gh run list --json --jq — all passthrough correctly with raw JSON output
• gh pr list, gh pr view 196, gh issue view 228 — RTK filtering still works, no regression

Minor nits (non-blocking):

• cargo fmt flags 2 formatting issues in tests
• Consider dropping -t/-q short flags from has_output_format_flags() — they could cause false positives if other gh subcommands reuse those short flags for something else. --json, --jq,
  --template are sufficient and unambiguous.

[pszymkowiak]

please review conflict to merge