feat(v1.1.2-docs): triggers framework + dispatcher + emitter extended for docs

The docs trigger kind hangs off the same Layout-E shape that v1.1.1
established for KV: a parent triggers row + a docs_trigger_details
row (collection_glob TEXT + ops TEXT[]) with the empty-array =
any-op semantic preserved.

- trigger_repo.rs adds TriggerKind::Docs + TriggerDetails::Docs +
  CreateDocsTrigger + DocsTriggerMatch + PostgresTriggerRepo
  implementations of create_docs_trigger and list_matching_docs.
  list_matching_docs mirrors KV's Rust-side filter (does NOT push
  ops membership into SQL — that would exclude empty-ops rows).
- outbox_repo.rs adds OutboxSourceKind::Docs to the enum + wire form.
- dispatcher.rs's generic Kv | DeadLetter routing arm extends to
  Kv | DeadLetter | Docs. No kind-specific logic needed — the
  resolve_trigger + build_exec_request path is already abstract.
- outbox_event_emitter.rs gains a "docs" arm in the emit match plus
  emit_docs which builds TriggerEvent::Docs (carrying data +
  prev_data) and fans out across matching triggers.
- triggers_api.rs adds CreateDocsTriggerRequest + create_docs_trigger
  + the POST /api/v1/admin/apps/{id}/triggers/docs route, all
  guarded by Capability::AppManageTriggers (same as KV).

3 new triggers_api unit tests covering happy path, empty-glob
rejection, and capability denial. All existing trigger-related
tests still pass.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

crates/manager-core/src/outbox_repo.rs

@@ -22,6 +22,8 @@ pub enum OutboxRepoError {
 pub enum OutboxSourceKind {
     Http,
     Kv,
+    /// v1.1.2.
+    Docs,
     DeadLetter,
 }
 
@@ -31,6 +33,7 @@ impl OutboxSourceKind {
         match self {
             Self::Http => "http",
             Self::Kv => "kv",
+            Self::Docs => "docs",
             Self::DeadLetter => "dead_letter",
         }
     }
@@ -40,6 +43,7 @@ impl OutboxSourceKind {
         match s {
             "http" => Some(Self::Http),
             "kv" => Some(Self::Kv),
+            "docs" => Some(Self::Docs),
             "dead_letter" => Some(Self::DeadLetter),
             _ => None,
         }