Feat event bus subscriptions + trigger system (v0.2.2)

Three trigger primitives replacing the old monolithic scheduler:

- Event triggers: extensions subscribe to bus patterns via manifest,
  async handler invocation through sandbox.CallEntryPoint
- Webhook triggers: inbound HTTP at /api/v1/hooks/:pkg/:slug with
  HMAC-SHA256 verification and synchronous Starlark response
- Scheduled tasks: user-created cron scripts with restricted sandbox
  (no raw HTTP, no DB table creation), runs as creator identity

New tables: triggers, scheduled_tasks, trigger_logs (postgres + sqlite).
New permission: triggers.register. Full admin + user CRUD APIs.
SyncManifestTriggers hooked into seed and install flows.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

server/store/trigger_iface.go

@@ -0,0 +1,45 @@
+package store
+
+import (
+	"context"
+	"time"
+
+	"switchboard-core/models"
+)
+
+// TriggerStore manages extension-declared event and webhook triggers.
+type TriggerStore interface {
+	// CRUD
+	Create(ctx context.Context, t *models.Trigger) error
+	GetByID(ctx context.Context, id string) (*models.Trigger, error)
+	Update(ctx context.Context, t *models.Trigger) error
+	Delete(ctx context.Context, id string) error
+
+	// Queries
+	List(ctx context.Context, opts TriggerListOptions) ([]models.Trigger, int, error)
+	ListByPackage(ctx context.Context, packageID string) ([]models.Trigger, error)
+	ListEnabledByType(ctx context.Context, triggerType string) ([]models.Trigger, error)
+
+	// Lifecycle
+	SetEnabled(ctx context.Context, id string, enabled bool) error
+	UpdateFireState(ctx context.Context, id string, lastFireAt time.Time, lastError string) error
+
+	// Webhook resolution
+	GetWebhook(ctx context.Context, packageID, slug string) (*models.Trigger, error)
+
+	// Cleanup
+	DeleteForPackage(ctx context.Context, packageID string) error
+
+	// Logs
+	LogExecution(ctx context.Context, log *models.TriggerLog) error
+	ListLogs(ctx context.Context, triggerID string, limit int) ([]models.TriggerLog, error)
+	PruneLogs(ctx context.Context, before time.Time) (int64, error)
+}
+
+// TriggerListOptions provides filtering for trigger list queries.
+type TriggerListOptions struct {
+	ListOptions
+	PackageID string
+	Type      string
+	Enabled   *bool
+}