kanban: make active_pr respawn guard opt-in (default off)

[sergeikabuldzhanov]

The active_pr respawn guard defers re-dispatch of any ready task whose recent comments contain a GitHub PR URL (check_respawn_guard, kanban_db.py). It assumes a worker already opened a PR and re-spawning risks a duplicate.

In a human-reviewed / human-merged workflow this is pure friction: a re-spawn can never silently land a duplicate or merged PR, yet a task that has produced a PR gets stuck in ready indefinitely (no --force dispatch flag exists in this version to override it). The other two guard reasons (blocker_auth, recent_success) remain useful and are unchanged.

Change

Gate only the active_pr branch behind HERMES_KANBAN_RESPAWN_GUARD_ACTIVE_PR (default off; set 1/true to restore the legacy behavior). blocker_auth, recent_success, and rate_limit_cooldown are untouched.

Tests

tests/hermes_cli/test_kanban_db.py updated to cover both states:

• test_respawn_guard_active_pr_disabled_by_default — PR-URL comment does NOT defer by default
• test_respawn_guard_active_pr_in_comment_when_enabled — opt-in flag restores deferral
• test_dispatch_active_pr_spawns_by_default — dispatch_once spawns a PR-commented task by default
• existing enabled-path tests gated behind the env var via monkeypatch

All 19 respawn-guard tests pass:

pytest tests/hermes_cli/test_kanban_db.py -k "respawn_guard or active_pr"
19 passed, 194 deselected

Backwards-compatible: anyone relying on the old behavior sets HERMES_KANBAN_RESPAWN_GUARD_ACTIVE_PR=1.

[teknium1]

Thanks for isolating the active_pr path and adding coverage for both proposed states.

This automated hermes-sweeper review is closing this under the standing configuration policy:

• The PR adds HERMES_KANBAN_RESPAWN_GUARD_ACTIVE_PR as a new user-facing, non-secret behavioral setting (hermes_cli/kanban_db.py, PR commit 0c5b0ff6dcf3). Hermes requires such settings to live in config.yaml, not a new HERMES_* environment variable.
• Current main intentionally retains the active_pr guard: check_respawn_guard() identifies a recent PR URL as a duplicate-PR risk (hermes_cli/kanban_db.py:7020-7023), and the Kanban docs describe it as preventing repeat worker storms (website/docs/user-guide/features/kanban.md:704-706).

If maintainers want this behavior configurable, please re-scope it to a documented kanban.* config.yaml setting integrated with the existing configuration path rather than an environment-variable toggle.

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Closed as not-planned per standing maintainer policy (env-var-for-config). This is a design-direction decision, not a code-quality judgment — see the Contribution Rubric in AGENTS.md for what the project is looking for. If you believe this policy was misapplied to your change, comment here and a maintainer will take a look.