refactor(kanban): fold worker/orchestrator skills into injected guidance (#50473)

The kanban-worker and kanban-orchestrator bundled skills existed only to
be force-loaded into dispatcher-spawned workers, gated by
environments:[kanban] so they wouldn't leak into normal CLI listings.
That gating was fragile (the leak that #50443 patched) and the
--skills auto-load was already best-effort — most workers ran without it
because the bundled skill isn't present in profile-scoped skills dirs.

Remove the skills entirely and promote their load-bearing content
(workspace kinds, deliverable artifacts, created-card integrity, profile
discovery) into KANBAN_GUIDANCE, which is already injected into every
kanban worker's system prompt. Net result: every worker reliably gets
the guidance, nothing can leak into a CLI/blank-slate session, and the
gating machinery is gone.

- agent/prompt_builder.py: promote the 4 load-bearing rules into KANBAN_GUIDANCE
- hermes_cli/kanban_db.py: drop --skills kanban-worker auto-injection + _kanban_worker_skill_available probe
- hermes_cli/kanban_swarm.py: drop skills=[kanban-orchestrator] on the root card
- hermes_cli/kanban.py: drop kanban-init skill seeding; fix help text
- delete skills/devops/kanban-{worker,orchestrator}
- docs: delete the two skill pages (EN+zh), fix sidebars/catalog/kanban.md/kanban-worker-lanes.md and the video-orchestrator + codex-lane references
- tests: update spawn-argv expectations; re-bound the guidance-size guard

Supersedes the skill-leak half of #50443 (credit @helix4u for flagging the area).

website/docs/reference/skills-catalog.md

@@ -62,8 +62,7 @@ If a skill is missing from this list but present in the repo, the catalog is reg
 
 | Skill | Description | Path |
 |-------|-------------|------|
-| [`kanban-orchestrator`](/docs/user-guide/skills/bundled/devops/devops-kanban-orchestrator) | Decomposition playbook + anti-temptation rules for an orchestrator profile routing work through Kanban. The "don't do the work yourself" rule and the basic lifecycle are auto-injected into every kanban worker's system prompt; this skill... | `devops/kanban-orchestrator` |
-| [`kanban-worker`](/docs/user-guide/skills/bundled/devops/devops-kanban-worker) | Pitfalls, examples, and edge cases for Hermes Kanban workers. The lifecycle itself is auto-injected into every worker's system prompt as KANBAN_GUIDANCE (from agent/prompt_builder.py); this skill is what you load when you want deeper det... | `devops/kanban-worker` |
+
 
 ## dogfood