feat(canary): Generator interface for token-type plugins

- ArtifactKind enum: url, file, text, connection_string
- Artifact struct discriminated by Kind
- TriggerResponse value-typed (handler writes; generator stays pure)
- Generator interface: Type, Generate, Trigger

PROJECTS/beginner/canary-token-generator/backend/internal/token/generators/generator.go

@@ -0,0 +1,45 @@
+// ©AngelaMos | 2026
+// generator.go
+
+package generators
+
+import (
+	"context"
+	"net/http"
+
+	"github.com/CarterPerez-dev/cybersecurity-projects/canary-token-generator/backend/internal/event"
+	"github.com/CarterPerez-dev/cybersecurity-projects/canary-token-generator/backend/internal/token"
+)
+
+type ArtifactKind string
+
+const (
+	KindURL              ArtifactKind = "url"
+	KindFile             ArtifactKind = "file"
+	KindText             ArtifactKind = "text"
+	KindConnectionString ArtifactKind = "connection_string"
+)
+
+type Artifact struct {
+	Kind             ArtifactKind
+	URL              string
+	Filename         string
+	Content          []byte
+	ContentType      string
+	ConnectionString string
+	DestinationURL   string
+}
+
+type TriggerResponse struct {
+	StatusCode   int
+	ContentType  string
+	Body         []byte
+	RedirectURL  string
+	ExtraHeaders map[string]string
+}
+
+type Generator interface {
+	Type() token.Type
+	Generate(ctx context.Context, t *token.Token, baseURL string) (Artifact, error)
+	Trigger(ctx context.Context, t *token.Token, r *http.Request) (*event.Event, *TriggerResponse, error)
+}