fix: surface active-pr respawn guards

[yunuenmf]

Summary

• include active PR respawn-guarded tasks in kanban dispatch dry-run JSON/plain output
• add a dedicated active_pr_respawn_guarded diagnostic so ready tasks blocked by review workflow are explicit instead of generic stranded-ready/no-spawn
• add regressions for dispatch output and diagnostic precedence

Test Plan

• python -m pytest tests/hermes_cli/test_kanban_cli.py tests/hermes_cli/test_kanban_diagnostics.py -q -o 'addopts='
• python -m pytest tests/hermes_cli/test_kanban_db.py tests/hermes_cli/test_kanban_cli_dispatch_passthrough.py -q -o 'addopts='

[yunuenmf]

Yunuen rejected this PR as superseded by the sticky blocked-task promotion fix on branch developer/kanban-blocked-promotion-fix. Please do not merge #34578. Blocker status: NOT BLOCKED — superseding PR will carry the deeper fix.

[yunuenmf]

Closing as rejected/superseded by the sticky blocked-task promotion fix, per Yunuen's Matrix review.