perf(actionsv2): execution target router (#10564)

# Which Problems Are Solved

The event execution system currently uses a projection handler that
subscribes to and processes all events for all instances. This creates a
high static cost because the system over-fetches event data, handling
many events that are not needed by most instances. This inefficiency is
also reflected in high "rows returned" metrics in the database.

# How the Problems Are Solved

Eliminate the use of a project handler. Instead, events for which
"execution targets" are defined, are directly pushed to the queue by the
eventstore. A Router is populated in the Instance object in the authz
middleware.

- By joining the execution targets to the instance, no additional
queries are needed anymore.
- As part of the instance object, execution targets are now cached as
well.
- Events are queued within the same transaction, giving transactional
guarantees on delivery.
- Uses the "insert many fast` variant of River. Multiple jobs are queued
in a single round-trip to the database.
- Fix compatibility with PostgreSQL 15

# Additional Changes

- The signing key was stored as plain-text in the river job payload in
the DB. This violated our [Secrets
Storage](https://zitadel.com/docs/concepts/architecture/secrets#secrets-storage)
principle. This change removed the field and only uses the encrypted
version of the signing key.
- Fixed the target ordering from descending to ascending.
- Some minor linter warnings on the use of `io.WriteString()`.

# Additional Context

- Introduced in https://github.com/zitadel/zitadel/pull/9249
- Closes https://github.com/zitadel/zitadel/issues/10553
- Closes https://github.com/zitadel/zitadel/issues/9832
- Closes https://github.com/zitadel/zitadel/issues/10372
- Closes https://github.com/zitadel/zitadel/issues/10492

---------

Co-authored-by: Stefan Benz <46600784+stebenz@users.noreply.github.com>
(cherry picked from commit a9ebc06c77)

internal/execution/worker_test.go

@@ -15,35 +15,21 @@ import (
 
 	"github.com/zitadel/zitadel/internal/api/authz"
 	"github.com/zitadel/zitadel/internal/eventstore"
-	"github.com/zitadel/zitadel/internal/execution/mock"
-	"github.com/zitadel/zitadel/internal/query"
+	target_domain "github.com/zitadel/zitadel/internal/execution/target"
 	"github.com/zitadel/zitadel/internal/repository/action"
 	exec_repo "github.com/zitadel/zitadel/internal/repository/execution"
 	"github.com/zitadel/zitadel/internal/repository/user"
 	"github.com/zitadel/zitadel/internal/zerrors"
 )
 
-type fields struct {
-	queries *mock.MockQueries
-	queue   *mock.MockQueue
-}
 type fieldsWorker struct {
 	now nowFunc
 }
-type args struct {
-	event  eventstore.Event
-	mapper func(event eventstore.Event) (eventstore.Event, error)
-}
 type argsWorker struct {
 	job *river.Job[*exec_repo.Request]
 }
-type want struct {
-	noOperation bool
-	err         assert.ErrorAssertionFunc
-	stmtErr     assert.ErrorAssertionFunc
-}
 type wantWorker struct {
-	targets        []*query.ExecutionTarget
+	targets        []target_domain.Target
 	sendStatusCode int
 	err            assert.ErrorAssertionFunc
 }
@@ -286,3 +272,25 @@ func Test_handleEventExecution(t *testing.T) {
 		})
 	}
 }
+
+func mockTarget() target_domain.Target {
+	return target_domain.Target{
+		ExecutionID:      "executionID",
+		TargetID:         "targetID",
+		TargetType:       target_domain.TargetTypeWebhook,
+		Endpoint:         "endpoint",
+		Timeout:          time.Minute,
+		InterruptOnError: true,
+	}
+}
+
+func mockTargets(count int) []target_domain.Target {
+	var targets []target_domain.Target
+	if count > 0 {
+		targets = make([]target_domain.Target, count)
+		for i := range targets {
+			targets[i] = mockTarget()
+		}
+	}
+	return targets
+}