feat(discovery/crawler): scaffold subpackage with Source interface and RawEvent types

backend/internal/domain/discovery/crawler/types.go

@@ -0,0 +1,63 @@
+// Package crawler scrapes five DACH Mittelalter event calendars and emits
+// RawEvent rows. The merger deduplicates across sources before the events
+// flow into the existing discovery pipeline (link verify, validate, dedup).
+package crawler
+
+import (
+	"context"
+	"time"
+)
+
+// Source is implemented by each calendar adapter.
+type Source interface {
+	Name() string
+	Fetch(ctx context.Context) ([]RawEvent, error)
+}
+
+// RawEvent is one event as reported by a single source before merging.
+type RawEvent struct {
+	SourceName string
+	SourceURL  string
+	DetailURL  string
+	Name       string
+	City       string
+	PLZ        string
+	Land       string
+	Bundesland string
+	StartDate  *time.Time
+	EndDate    *time.Time
+	Website    string
+	Venue      string
+	Organizer  string
+}
+
+// MergedEvent is one event after cross-source merging. Quellen holds the union
+// of source URLs, Hinweis carries merger-generated notes (date_conflict, etc.).
+type MergedEvent struct {
+	Name       string
+	City       string
+	PLZ        string
+	Land       string
+	Bundesland string
+	StartDate  *time.Time
+	EndDate    *time.Time
+	Website    string
+	Venue      string
+	Organizer  string
+	Quellen    []string
+	Hinweis    string
+	Sources    []string
+}
+
+// SourceError records a per-source failure without stopping the whole crawl.
+type SourceError struct {
+	Name string
+	Err  error
+}
+
+// CrawlResult is what the orchestrator returns to Service.Crawl.
+type CrawlResult struct {
+	PerSource    map[string][]RawEvent
+	SourceErrors []SourceError
+	PerSourceMS  map[string]int64
+}