fix(schema): 입금자명 길이 제한 50자 → 15자로 조정

근거:
- SMS 입금자명: 한글 7자 제한 (은행 시스템)
- 사용자 수동 입력: 15자로 충분한 여유
- 매칭 로직: 앞 7자만 사용

변경사항:
- CHECK (length(depositor_name) <= 50) → 15
- 데이터 복원 시 truncate: 50자 → 15자
- SCHEMA_MIGRATION_GUIDE.md 업데이트
- MIGRATION_SUMMARY.md 업데이트

로컬 테스트 결과:
- ✅ 15자 이하: 정상 입력
  - 숫자 15자: "123456789012345" ✓
  - 한글 15자: "홍길동아버지어머니할머님고모고" ✓
- ✅ 16자 이상: 거부됨
  - 숫자 16자: "1234567890123456" ✗ (CHECK 제약조건)
  - 한글 16자: "홍길동아버지어머니할머님고모고모" ✗ (CHECK 제약조건)

실용성:
- SMS 7자 보장 + 사용자 입력 여유
- 불필요한 긴 이름 방지
- 매칭 로직과 완벽 호환

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

MIGRATION_SUMMARY.md

@@ -13,7 +13,7 @@ Database migration to add critical data integrity constraints and audit logging
 | Component | Change | Impact |
 |-----------|--------|--------|
 | `user_deposits.balance` | Add CHECK (balance >= 0) | Prevents negative balances |
-| `deposit_transactions.depositor_name` | Add CHECK (length <= 50) | Enforces name length limit |
+| `deposit_transactions.depositor_name` | Add CHECK (length <= 15) | Enforces name length limit |
 | `audit_logs` | New table | Tracks all critical operations |
 
 ### Risk Assessment
@@ -50,7 +50,7 @@ telegram-bot-workers/
 - [ ] Read `SCHEMA_MIGRATION_GUIDE.md` completely
 - [ ] Backup production database
 - [ ] Check for negative balances in production
-- [ ] Check for long depositor names (> 50 chars) in production
+- [ ] Check for long depositor names (> 15 chars) in production
 - [ ] Verify rollback script is accessible
 - [ ] Schedule deployment window (< 5 min)
 - [ ] Notify stakeholders (optional)
@@ -209,18 +209,18 @@ balance INTEGER NOT NULL DEFAULT 0 CHECK (balance >= 0)
 CHECK constraint failed: balance >= 0
 ```
 
-### Depositor Name Length <= 50 (deposit_transactions)
+### Depositor Name Length <= 15 (deposit_transactions)
 
-**Why**: Bank SMS truncates names at 7 chars, but we allow 50 for edge cases
+**Why**: Bank SMS truncates names at 7 chars, but we allow 15 for flexibility
 
 **Implementation**:
 ```sql
-depositor_name TEXT CHECK (length(depositor_name) <= 50)
+depositor_name TEXT CHECK (length(depositor_name) <= 15)
 ```
 
 **Effect**: Names longer than 50 chars will be rejected:
 ```
-CHECK constraint failed: length(depositor_name) <= 50
+CHECK constraint failed: length(depositor_name) <= 15
 ```
 
 ---
@@ -282,7 +282,7 @@ wrangler d1 execute telegram-conversations \
    # Check for long names
    wrangler d1 execute telegram-conversations \
      --command "SELECT id, depositor_name, length(depositor_name) as len
-                FROM deposit_transactions WHERE length(depositor_name) > 50"
+                FROM deposit_transactions WHERE length(depositor_name) > 15"
    ```
 
 3. **Prepare Backup**

SCHEMA_MIGRATION_GUIDE.md

@@ -13,7 +13,7 @@ This migration adds critical data integrity constraints and audit logging capabi
 | Change | Purpose | Risk Level |
 |--------|---------|------------|
 | `user_deposits.balance` CHECK constraint | Prevent negative balances | Medium |
-| `deposit_transactions.depositor_name` length limit | Enforce 50 character max | Low |
+| `deposit_transactions.depositor_name` length limit | Enforce 15 character max | Low |
 | `audit_logs` table | Track all important operations | None (new table) |
 
 ---
@@ -46,20 +46,20 @@ INSERT INTO user_deposits (user_id, balance) VALUES (999999, -1000);
 
 ### 2. Depositor Name Length (`deposit_transactions`)
 
-**Goal**: Limit `depositor_name` to 50 characters max
+**Goal**: Limit `depositor_name` to 15 characters max
 
 **Implementation**:
 ```sql
 CREATE TABLE deposit_transactions (
   ...
-  depositor_name TEXT CHECK (length(depositor_name) <= 50),
+  depositor_name TEXT CHECK (length(depositor_name) <= 15),
   ...
 );
 ```
 
 **Impact**:
 - ✅ Prevents excessively long names
-- 📏 Truncates existing names >50 chars (logs truncated records)
+- 📏 Truncates existing names >15 chars (logs truncated records)
 - 🔧 Requires table recreation (SQLite limitation)
 
 **Verification**:
@@ -137,7 +137,7 @@ wrangler d1 execute telegram-conversations \
 
 # Check for long depositor names (will be truncated)
 wrangler d1 execute telegram-conversations \
-  --command "SELECT id, depositor_name, length(depositor_name) as len FROM deposit_transactions WHERE length(depositor_name) > 50"
+  --command "SELECT id, depositor_name, length(depositor_name) as len FROM deposit_transactions WHERE length(depositor_name) > 15"
 ```
 
 ### 3. Notify Users (if downtime expected)
@@ -496,7 +496,7 @@ wrangler d1 execute telegram-conversations \
 After migration, verify:
 
 - [ ] All user_deposits records have `balance >= 0`
-- [ ] All deposit_transactions have `depositor_name` length <= 50
+- [ ] All deposit_transactions have `depositor_name` length <= 15
 - [ ] audit_logs table exists with correct schema
 - [ ] All indexes recreated successfully
 - [ ] Record counts match pre-migration

migrations/001_schema_enhancements.sql

@@ -59,7 +59,7 @@ CREATE TABLE deposit_transactions (
   type TEXT NOT NULL CHECK(type IN ('deposit', 'withdrawal', 'refund')),
   amount INTEGER NOT NULL,
   status TEXT NOT NULL DEFAULT 'pending' CHECK(status IN ('pending', 'confirmed', 'rejected', 'cancelled')),
-  depositor_name TEXT CHECK (length(depositor_name) <= 50),
+  depositor_name TEXT CHECK (length(depositor_name) <= 15),
   description TEXT,
   confirmed_at DATETIME,
   created_at DATETIME DEFAULT CURRENT_TIMESTAMP,
@@ -78,7 +78,7 @@ SELECT
   status,
   CASE
     WHEN depositor_name IS NULL THEN NULL
-    WHEN length(depositor_name) > 50 THEN substr(depositor_name, 1, 50)
+    WHEN length(depositor_name) > 15 THEN substr(depositor_name, 1, 15)
     ELSE depositor_name
   END as depositor_name,
   description,
@@ -89,7 +89,7 @@ FROM deposit_transactions_backup;
 -- 2.5 Log truncated records (if any)
 SELECT 'TRUNCATED DEPOSITOR NAME:' as warning, id, depositor_name, length(depositor_name) as original_length
 FROM deposit_transactions_backup
-WHERE depositor_name IS NOT NULL AND length(depositor_name) > 50;
+WHERE depositor_name IS NOT NULL AND length(depositor_name) > 15;
 
 -- 2.6 Drop backup table
 DROP TABLE deposit_transactions_backup;