fix: remediate severity-ordered review findings across cache, scanners, and proxies

- H2: gormstore soft-delete + storage_key UNIQUE collision; re-save after eviction succeeds
- H1: cache getOrFetch cache-hit branch no longer runs CheckVulnerabilities on metadata entries
- M2: cache store() streams upstream body to temp file + SHA256 instead of double-buffering
- H3/L3: FetchResult/FetchFunc plumbing (+RequiresAuth/AuthProvider); proxy closures adapted;
        goproxy strips git+ prefix from UpstreamURL
- H4: scanner normalizes bypass package names; CheckVulnerabilities builds normalized packageKey
- M4: requireAdmin routes through extractAPIKey -> ValidateAPIKey -> admin role check
- M5: network client keeps only final RecordFailure (one count per attempt cycle)
- M3: normalizeOriginHost + buildCheckOrigin rewrite; origin_test.go added
- M1: app lifecycle cancel func; Run -> Shutdown on listen error (sole cache owner); JoinHostPort
- M6: VulnerabilityThresholds defaults all -1 so BlockOnSeverity governs
- L4: metadata.NormalizeSeverity at 4 severity-count sites (MEDIUM->MODERATE consistency)
- L1: handleDeleteBypass uses structured *errors.Error + ErrCodeNotFound
- L2: pypi extractVersionFromFilename (wheel/2nd segment, non-wheel/last digit segment);
      cacheVersion uses full unique basename; regression tests added
- L5: document per-instance ValidationCache key scoping; rename packageURL param to resource

All: go build ./... && go vet ./... && go test ./... pass; golangci-lint clean.

pkg/app/origin_test.go

@@ -0,0 +1,73 @@
+package app
+
+import (
+	"net/http"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func reqWithOrigin(origin string) *http.Request {
+	r, _ := http.NewRequest(http.MethodGet, "/ws", nil)
+	if origin != "" {
+		r.Header.Set("Origin", origin)
+	}
+	r.Host = "app.example.com"
+	return r
+}
+
+// TestBuildCheckOrigin_DefaultPortNormalization verifies that scheme-default
+// ports (443/80) are ignored, so "https://app.example.com" and
+// "https://app.example.com:443" are treated as the same origin.
+func TestBuildCheckOrigin_DefaultPortNormalization(t *testing.T) {
+	check := buildCheckOrigin([]string{"https://app.example.com"})
+
+	assert.True(t, check(reqWithOrigin("https://app.example.com")))
+	assert.True(t, check(reqWithOrigin("https://app.example.com:443")))
+	assert.False(t, check(reqWithOrigin("https://app.example.com:8443")))
+
+	// Default http port strips too.
+	checkHTTP := buildCheckOrigin([]string{"http://app.example.com"})
+	assert.True(t, checkHTTP(reqWithOrigin("http://app.example.com:80")))
+	assert.True(t, checkHTTP(reqWithOrigin("http://app.example.com")))
+}
+
+// TestBuildCheckOrigin_NonDefaultPortPreserved verifies a non-default port is
+// not stripped and must match exactly.
+func TestBuildCheckOrigin_NonDefaultPortPreserved(t *testing.T) {
+	check := buildCheckOrigin([]string{"https://app.example.com:8443"})
+
+	assert.True(t, check(reqWithOrigin("https://app.example.com:8443")))
+	assert.False(t, check(reqWithOrigin("https://app.example.com")))
+}
+
+// TestBuildCheckOrigin_Wildcard verifies wildcard host patterns match the apex
+// and subdomains, and are unaffected by ports on the incoming origin.
+func TestBuildCheckOrigin_Wildcard(t *testing.T) {
+	check := buildCheckOrigin([]string{"https://*.example.com"})
+
+	assert.True(t, check(reqWithOrigin("https://example.com")))
+	assert.True(t, check(reqWithOrigin("https://cdn.example.com")))
+	assert.True(t, check(reqWithOrigin("https://cdn.example.com:443")))
+	assert.False(t, check(reqWithOrigin("https://example.org")))
+}
+
+// TestBuildCheckOrigin_SchemeMismatch verifies the scheme must match.
+func TestBuildCheckOrigin_SchemeMismatch(t *testing.T) {
+	check := buildCheckOrigin([]string{"https://app.example.com"})
+
+	assert.False(t, check(reqWithOrigin("http://app.example.com")))
+}
+
+// TestBuildCheckOrigin_SameOriginFallback verifies that with an empty allowlist
+// only a same-origin upgrade (matching Host) is permitted.
+func TestBuildCheckOrigin_SameOriginFallback(t *testing.T) {
+	check := buildCheckOrigin(nil)
+
+	r := reqWithOrigin("https://app.example.com")
+	assert.True(t, check(r))
+
+	// Host defaults to app.example.com; a different Origin host is rejected.
+	r2 := reqWithOrigin("https://other.example.com")
+	assert.False(t, check(r2))
+}