feat(v1.1.6): realtime channels + v1.1.5 follow-ups + version bumps

Server-side realtime SSE on per-app pub/sub topics, plus the three
v1.1.5 follow-ups and the version bumps.

Realtime:
- topics registry (0021) + admin endpoints + Capability::AppTopicManage
  (-> app:admin; no new scope).
- GET /realtime/topics/{topic} SSE endpoint (orchestrator-core data
  plane): Host -> app, RealtimeAuthority gate (404 missing/internal,
  401 bad/absent token), broadcast::Receiver stream + heartbeat.
- RealtimeBroadcaster / RealtimeEvent / RealtimeAuthority traits
  (picloud-shared); InProcessBroadcaster + GC (orchestrator-core);
  DB-backed RealtimeAuthorityImpl (manager-core). Publish path fans out
  to in-process subscribers after the durable outbox commit (best-effort,
  panic-isolated).
- HMAC subscriber tokens (subscriber_token.rs) + app_secrets table (0022)
  + pubsub::subscriber_token SDK (schema 1.6 -> 1.7). TTL clamp + env
  overrides.
- Dashboard Topics tab (register/list/edit/delete, prominent external
  badge, flip confirmation).

v1.1.5 follow-ups:
- Empty blobs accepted (NewFile/FileUpdate::validate) + round-trip test.
- Orphan *.tmp.* sweeper (spawn_files_orphan_sweep).
- Dispatcher e2e tests, one per trigger kind (DATABASE_URL-gated).

Versions: workspace 1.1.6, SDK 1.7, dashboard 0.12.0. Schema-snapshot
golden re-blessed.

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

crates/manager-core/migrations/0021_topics.sql

@@ -0,0 +1,31 @@
+-- v1.1.6: Explicit registration for externally-subscribable topics.
+--
+-- Internal-only topics remain implicit per the §5 design-notes
+-- decision: anyone can publish_durable("any.topic", msg) and triggers
+-- can subscribe without a row here. This table only holds topics that
+-- have been explicitly externalized — external SSE subscribers can
+-- only subscribe to topics with a row here AND external_subscribable
+-- = TRUE.
+--
+-- The publish path (v1.1.5's publish_durable) does NOT consult this
+-- table: publishing to a topic with no row still fans out to triggers
+-- and to any in-process external subscribers (none exist for an
+-- unregistered topic, since external subscribers can't subscribe to
+-- one). The topics table is read by the SSE subscribe path only.
+--
+-- auth_mode values: 'public' + 'token' in v1.1.6. 'session' arrives in
+-- v1.1.8 (users-SDK); 'script' arrives in v1.2 (script-mediated auth).
+-- The CHECK constraint extends in those releases.
+CREATE TABLE topics (
+    app_id                UUID NOT NULL REFERENCES apps(id) ON DELETE CASCADE,
+    name                  TEXT NOT NULL,
+    external_subscribable BOOL NOT NULL DEFAULT FALSE,
+    auth_mode             TEXT NOT NULL DEFAULT 'public'
+        CHECK (auth_mode IN ('public', 'token')),
+    created_at            TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+    updated_at            TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+    PRIMARY KEY (app_id, name)
+);
+
+-- Hot lookup: "is topic T in app X externally subscribable?" The PK
+-- (app_id, name) already covers this; an explicit index is redundant.