feat: initialize project structure with SQLite database, crawler framework, and LLM-based JD analysis integration

internal/crawler/crawler.go

@@ -0,0 +1,32 @@
+package crawler
+
+import (
+	"context"
+	"crypto/sha256"
+	"fmt"
+)
+
+type DiscoveredJob struct {
+	CanonicalID string
+	ApplyURL    string
+}
+
+type ExtractedJob struct {
+	CanonicalID string
+	Title       string
+	Company     string
+	Location    string
+	ApplyURL    string
+	RawContent  string
+}
+
+func GenerateCanonicalID(company, title, applyURL string) string {
+	data := fmt.Sprintf("%s|%s|%s", company, title, applyURL)
+	return fmt.Sprintf("%x", sha256.Sum256([]byte(data)))
+}
+
+type SiteCrawler interface {
+	CanHandle(platform string) bool
+	DiscoverJobs(ctx context.Context, targetURL string) ([]DiscoveredJob, error)
+	FetchJobDetail(ctx context.Context, applyURL string) (*ExtractedJob, error)
+}