fix(kanban): don't flag dispatcher stuck when ready tasks are respawn-guard deferred (#80513)

[Enough1122]

Fixes #80513

Root cause

The dispatcher health telemetry's has_spawnable_ready() counted ready+assigned+unclaimed tasks without consulting the respawn guard — but dispatch_once deliberately defers exactly those tasks every tick (recent_success / active_pr / rate_limit_cooldown / blocker_auth). An idle-by-design board therefore read as "spawnable work waiting", producing endless false "kanban dispatcher stuck" alarms (~986 false ticks observed by the reporter).

Fix

Both probes (has_spawnable_ready + mirror has_spawnable_review) now route through a shared _has_spawnable_in_lane(): a task counts as spawnable only when its assignee is a real profile AND check_respawn_guard() does not defer it this tick. Unexpected guard errors fail conservative (legacy warn behavior preserved), and both warn sites (CLI daemon + gateway watcher) now annotate the warning with that tick's guard deferrals so operators can split parked tasks from genuinely broken spawns. Dispatch semantics untouched — the probes' only callers are the two telemetry warn sites.

Verification

• 11 new behavior-contract tests ( ests/hermes_cli/test_kanban_stuck_telemetry.py): no warning on an all-guarded board (and zero spawn attempts), warning fires on truly-spawnable-unspawned, mixed boards warn AND list deferrals, window-expiry re-enables, CLI daemon E2E via real dispatch_once.
• scripts/run_tests.sh over the new file + est_kanban_review_lifecycle.py + est_kanban_watchers_mixin.py → 31 passed, 0 failed.

[alt-glitch]

This was generated by AI during triage.

Related: #44899 is an earlier open fix for respawn-guarded tasks being counted as spawnable. This PR overlaps that ready-lane repair and additionally covers review-lane telemetry and diagnostic context; maintainers should choose or consolidate the approaches.

[Enough1122]

Closing as part of an open-queue triage — consolidating my open work so review attention goes to the highest-value changes. Nothing here is abandoned: happy to reopen (or rebase fresh) if there's interest or reviewer bandwidth.