Coverage priorities 1-5: test pure functions, extract interfaces, mock-based handler tests

- Priority 1: Test NewSendEmailTask + NewSendPushTask (5 tests)
- Priority 2: Test customHTTPErrorHandler — all 15+ branches (21 tests)
- Priority 3: Extract Enqueuer interface + payload builders in worker pkg (5 tests)
- Priority 4: Extract ClassifyFile/ComputeRelPath in migrate-encrypt (6 tests)
- Priority 5: Define Handler interfaces, refactor to accept them, mock-based tests (14 tests)
- Fix .gitignore: /worker instead of worker to stop ignoring internal/worker/

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

cmd/worker/startup.go

@@ -0,0 +1,24 @@
+package main
+
+import "github.com/treytartt/honeydue-api/internal/worker/jobs"
+
+// queuePriorities returns the Asynq queue priority map.
+func queuePriorities() map[string]int {
+	return map[string]int{
+		"critical": 6,
+		"default":  3,
+		"low":      1,
+	}
+}
+
+// allJobTypes returns all registered job type strings.
+func allJobTypes() []string {
+	return []string{
+		jobs.TypeSmartReminder,
+		jobs.TypeDailyDigest,
+		jobs.TypeSendEmail,
+		jobs.TypeSendPush,
+		jobs.TypeOnboardingEmails,
+		jobs.TypeReminderLogCleanup,
+	}
+}