feat(dönem): dönem açma, açık dönem, düzenleme ve haftalar (backend)

- /api/periods: liste, açık dönem, aç, detay, düzenle
- Kurallar: tek açık dönem, çakışma yok, bitiş hariç, en fazla 62 gün, kapalı dönem salt okunur
- Tarih daraltılırken dışarıda harcama kalırsa engellenir
- Haftalar Pazartesi başlangıçlı, kısmi haftalar ayrı (takvim yardımcıları)
- Otomatik dönem adı: "Aralık 2026" / "15 Ara 2026 – 14 Oca 2027"
- Testler: takvim (4), dönem kuralları (2), entegrasyon (5)

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

frontend/src/types/Period.ts

@@ -0,0 +1,21 @@
+// This file was generated by [ts-rs](https://github.com/Aleph-Alpha/ts-rs). Do not edit this file manually.
+import type { PeriodStatus } from "./PeriodStatus";
+import type { PeriodWeek } from "./PeriodWeek";
+
+export type Period = { id: string, name: string, 
+/**
+ * Dahil
+ */
+start_date: string, 
+/**
+ * Hariç (veritabanındaki değer)
+ */
+end_date: string, 
+/**
+ * Son gün, dahil (gösterim için)
+ */
+last_date: string, days: number, status: PeriodStatus, 
+/**
+ * Kuruş
+ */
+savings_goal: number, version: number, weeks: Array<PeriodWeek>, };

frontend/src/types/PeriodCreateRequest.ts

@@ -0,0 +1,19 @@
+// This file was generated by [ts-rs](https://github.com/Aleph-Alpha/ts-rs). Do not edit this file manually.
+
+export type PeriodCreateRequest = { 
+/**
+ * `"YYYY-MM-DD"`, dahil
+ */
+start_date: string, 
+/**
+ * `"YYYY-MM-DD"`, hariç (ör. Aralık için `2027-01-01`)
+ */
+end_date: string, 
+/**
+ * Boşsa otomatik ("Aralık 2026")
+ */
+name?: string, 
+/**
+ * Kuruş
+ */
+savings_goal?: number, };

frontend/src/types/PeriodStatus.ts

@@ -0,0 +1,3 @@
+// This file was generated by [ts-rs](https://github.com/Aleph-Alpha/ts-rs). Do not edit this file manually.
+
+export type PeriodStatus = "open" | "closed";

frontend/src/types/PeriodUpdateRequest.ts

@@ -0,0 +1,3 @@
+// This file was generated by [ts-rs](https://github.com/Aleph-Alpha/ts-rs). Do not edit this file manually.
+
+export type PeriodUpdateRequest = { name?: string, start_date?: string, end_date?: string, savings_goal?: number, version?: number, };

frontend/src/types/PeriodWeek.ts

@@ -0,0 +1,11 @@
+// This file was generated by [ts-rs](https://github.com/Aleph-Alpha/ts-rs). Do not edit this file manually.
+
+export type PeriodWeek = { 
+/**
+ * 1'den başlar
+ */
+index: number, start_date: string, 
+/**
+ * Dahil
+ */
+last_date: string, days: number, };