* feat(kanban): typed block reasons + unblock-loop breaker
Stops the kanban blocked-task loop: a worker blocks a task, a cron
unblocks it, the worker re-blocks for the same reason, repeat forever.
block_task now takes a typed kind and a persistent block_recurrences
counter on the tasks table:
- kind=dependency routes to todo (parent-gated, auto-resumed), never
the human 'blocked' bucket a cron would keep unblocking.
- needs_input/capability/transient/untyped land in blocked; each
same-cause re-block after an unblock increments block_recurrences,
and at BLOCK_RECURRENCE_LIMIT (default 2) the task routes to triage
for a human instead of blocked.
- unblock_task no longer resets block_recurrences (the amnesia that
let the loop run unbounded); complete_task clears it on success.
Wired through the worker kanban_block tool (new kind arg) and the
hermes kanban block --kind CLI flag, both reporting where the task
actually landed. Docs + 11 new tests; 536 existing kanban tests green.
* test(kanban): make second-block notify test use a distinct block cause
test_notifier_second_blocked_delivers blocked the same task twice with
the same (untyped) reason, which now trips the new unblock-loop breaker
and routes the second block to triage instead of blocked — so only one
'blocked' notification fired. The test's actual intent is that TWO
distinct block cycles each notify; give the two cycles different kinds
(needs_input then capability) so they're genuinely separate blocks. The
same-cause loop→triage path is covered by test_kanban_block_kinds.py.