feat(plugins): official plugins ship compile-able ./services entrypoints

[rickylabs]

Gap G5 (eis-chat#150 forensics): the workers plugin needed a hand-synthesized compile entry; streams already ships /services. Every official plugin ships a compile-able ./services-style entrypoint — pure start functions (no config-time env side effects), consuming the PM-B watcher (#828) in supervised mode.

• gate: per-plugin deno compile smoke; scaffold.plugins green
• gate: full jsr rubric per entrypoint (@module + example; no app-only types in the public graph; portable)
• gate: publish dry-run

Depends on #828. Design source: PR #822 (rfc.md + plan.md rev 10, 9-cycle adversarial trail) in .llm/runs/rfc-single-deployment--orchestrator/. (plan.md §E.2)