feat(v1.1.5): pubsub::publish_durable SDK + pubsub:* triggers

Durable pub/sub through the universal outbox — the sixth trigger kind.

- `pubsub::publish_durable(topic, message)` Rhai SDK (no handle; topics
  ARE the grouping unit). Message JSON-encoded; Blobs base64 at any
  depth.
- `PubsubService` trait in picloud-shared with the topic matcher +
  validator (exact / `<prefix>.*` / `*`; mid-pattern wildcards
  rejected). `PostgresPubsubRepo` + `PubsubServiceImpl` in manager-core.
- Publish-time fan-out: one outbox row per matching enabled pubsub
  trigger, all in ONE transaction (no half-fan-out on crash). No
  matching trigger → publish succeeds silently, zero rows.
- `pubsub:*` trigger kind via Layout-E (0020: widen both CHECKs +
  pubsub_trigger_details + partial index), TriggerEvent::Pubsub +
  ctx.event.pubsub, dispatcher arm, admin endpoint POST /triggers/pubsub
  (validates topic pattern + reuses validate_trigger_target).
- AppPubsubPublish capability → script:write (seven-scope held).
- Dashboard Pub/Sub trigger form on the Triggers tab + list rendering.

publish_ephemeral stays deferred to v1.2. ~18 new tests (service
in-memory incl. transactional-rollback, shared matcher, bridge
encoding). No DB required for the suite.

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

crates/shared/src/lib.rs

@@ -20,6 +20,7 @@ pub mod kv;
 pub mod log_sink;
 pub mod modules;
 pub mod outbox_writer;
+pub mod pubsub;
 pub mod route;
 pub mod sandbox;
 pub mod script;
@@ -50,6 +51,9 @@ pub use kv::{KvError, KvListPage, KvService, NoopKvService};
 pub use log_sink::{ExecutionLogSink, LogSinkError};
 pub use modules::{ModuleScript, ModuleSource, ModuleSourceError, NoopModuleSource};
 pub use outbox_writer::{HttpDispatchPayload, NewHttpOutbox, OutboxWriter, OutboxWriterError};
+pub use pubsub::{
+    topic_matches, validate_topic_pattern, NoopPubsubService, PubsubError, PubsubService,
+};
 pub use route::{DispatchMode, HostKind, PathKind, Route};
 pub use sandbox::ScriptSandbox;
 pub use script::{Script, ScriptKind};