test/docs(shared-queues): journey + docs (D3.3)

CLI journey (shared_queues): authoring + `pic triggers ls --group` shared
column + the two validation rejections (undeclared queue collection; shared
on an app), mirroring the shared_topics/shared_triggers norm; the live
competing-consumer + dispatcher behaviour is pinned by the deterministic
manager-core tests. Docs: CLAUDE.md + design doc §11.6 record D3 as shipped.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

crates/picloud-cli/tests/cli.rs

@@ -43,6 +43,7 @@ mod routes;
 mod scripts;
 mod sealed;
 mod secrets;
+mod shared_queues;
 mod shared_topics;
 mod shared_triggers;
 mod staleness;