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/manager-core/migrations/0020_pubsub_triggers.sql

@@ -0,0 +1,34 @@
+-- v1.1.5: extend the triggers framework to recognise `pubsub` as the
+-- sixth concrete kind. Same Layout-E shape as files (0019): two CHECK
+-- constraints widen, one new detail table.
+--
+-- Pub/sub fans out at PUBLISH time (one outbox row per matching trigger,
+-- written by the PubsubServiceImpl), so the dispatcher needs no pubsub-
+-- specific branching — a pubsub outbox row dispatches like any other
+-- async trigger.
+
+-- Extend triggers.kind to include 'pubsub'.
+ALTER TABLE triggers DROP CONSTRAINT triggers_kind_check;
+ALTER TABLE triggers ADD CONSTRAINT triggers_kind_check
+    CHECK (kind IN ('kv', 'dead_letter', 'docs', 'cron', 'files', 'pubsub'));
+
+-- Extend outbox.source_kind to include 'pubsub'.
+ALTER TABLE outbox DROP CONSTRAINT outbox_source_kind_check;
+ALTER TABLE outbox ADD CONSTRAINT outbox_source_kind_check
+    CHECK (source_kind IN ('http', 'kv', 'dead_letter', 'docs',
+                           'cron', 'files', 'pubsub'));
+
+-- One row per pubsub trigger. `topic_pattern` is "exact", "prefix.*",
+-- or "*" — validated in Rust at trigger creation. Topics are implicit
+-- on first publish; the external-subscribable `topics` table is v1.1.6.
+CREATE TABLE pubsub_trigger_details (
+    trigger_id     UUID PRIMARY KEY REFERENCES triggers(id) ON DELETE CASCADE,
+    topic_pattern  TEXT NOT NULL
+);
+
+-- Hot lookup for fan-out: "all enabled pubsub triggers in app X".
+-- Third partial index of its kind (after v1.1.1's idx_triggers_app_kind_
+-- enabled); partial indexes are tiny and the planner picks the narrowest.
+CREATE INDEX idx_triggers_app_pubsub_enabled
+    ON triggers (app_id, kind)
+    WHERE enabled = TRUE AND kind = 'pubsub';