[#48] FEAT: 파트너 일·월별 품목 통계 조회 API 구현, 'TradeItem'에 netPayloadWeight 컬럼 추가 및 관련사항 리팩토링, '파트너 통계 조회 API' 권한을 파트너와 관리자로 분리, Flyway 설정 및 문서/스킬 통합

.claude/skills/GUIDELINES.md

@@ -57,6 +57,12 @@ A **Skill** is a scoped, reusable workflow that encodes:
 - Many detailed examples needed
 - Separate reference material helps token efficiency
 
+### Korean Translation Requirement (MUST)
+
+When you create or update a skill:
+- ALSO create/update a Korean translation at `.claude/skills/<skill-name>/md-ko-ver/SKILL.md`.
+- Ensure the file is saved as UTF-8 (한글 인코딩 깨짐 방지).
+
 ---
 
 ## Required Sections

.claude/skills/flyway/SKILL.md

@@ -0,0 +1,245 @@
+---
+name: flyway
+description: >
+  Use this skill when creating or modifying database schema migrations or
+  resolving Flyway validation/repair issues. It enforces immutable migrations,
+  ddl-auto=validate usage, safe backfills, and profile-scoped auto-repair rules.
+---
+
+# Flyway Migrations
+
+Use Flyway for all schema changes and migration recovery. This skill is scoped
+to database schema workflow only.
+
+## When to Activate
+
+Use this skill when:
+- Creating or editing a SQL migration under `src/main/resources/db/migration`
+- Adding or changing JPA entity fields that require schema updates
+- Handling Flyway errors (checksum mismatch, failed validation, failed migrate)
+- Planning a baseline (initial schema) migration for clean environments
+- Changing DDL-related settings (e.g., `ddl-auto`)
+
+## Out of Scope (DO NOT use this skill)
+
+- Business logic changes unrelated to schema
+- Data correction scripts not tied to schema evolution
+- Performance tuning, query optimization, or index analysis only
+- Test data cleanup (see `test-code` skill)
+
+---
+
+# Core Rules/Principles
+
+## 🚨 CRITICAL: NEVER edit an applied migration
+
+**Rule:** Once a migration version is applied to any DB, do NOT modify or delete
+its SQL file. Always add a new migration.
+
+**Why this matters:**
+- Editing breaks Flyway checksum validation.
+- Inconsistent environments lead to irreversible schema drift.
+
+## MUST: Use Flyway for all schema changes
+
+All schema changes MUST be represented as Flyway migrations in
+`src/main/resources/db/migration`.
+
+**Why this matters:** `ddl-auto` is set to `validate`, so Hibernate will not
+modify schemas. Without Flyway migrations, the app will fail to boot.
+
+## MUST: Keep `ddl-auto=validate`
+
+Never commit `ddl-auto=update/create`. Use `validate` across profiles.
+
+**Why this matters:** Automatic schema mutation bypasses versioned migrations
+and makes reproducible environments impossible.
+
+## IMPORTANT: Auto-repair is dev/test only
+
+Auto-repair is enabled for `local`, `test`, and `test-dev` profiles only.
+Never enable auto-repair in production.
+
+**Why this matters:** Repair can hide accidental migration edits. Production
+must fail fast and require explicit review.
+
+## IMPORTANT: NOT NULL changes require safe backfill
+
+Use the pattern: add nullable column -> backfill -> set NOT NULL.
+
+**Why this matters:** Avoids startup failures and partial updates.
+
+---
+
+# Workflow
+
+## Step 1: Determine Change Scope
+
+**DO:**
+- Identify which entities/fields require schema changes.
+- Search for existing migrations covering the same change.
+
+**DO NOT:**
+- Modify an existing migration file.
+
+**Verify:**
+- [ ] No existing migration already covers the change.
+
+**Output:** A clear list of schema changes.
+
+## Step 2: Create a New Migration
+
+**DO:**
+- Create a new SQL file under `src/main/resources/db/migration`.
+- Use naming: `VYYYYMMDD__short_description.sql`.
+
+**DO NOT:**
+- Use vague names like `update.sql`.
+
+**Verify:**
+- [ ] Filename is unique and ordered.
+- [ ] SQL is idempotent when possible (e.g., `IF NOT EXISTS` for columns).
+
+**Output:** New migration file path.
+
+## Step 3: Handle Backfills Safely
+
+**DO:**
+- For NOT NULL: add nullable column -> backfill -> set NOT NULL.
+- Use deterministic backfills (no random values).
+
+**DO NOT:**
+- Skip backfill and apply NOT NULL immediately.
+
+**Verify:**
+- [ ] Backfill covers all existing rows.
+- [ ] Constraints applied after backfill.
+
+**Output:** Backfill SQL steps.
+
+## Step 4: Validate and Apply
+
+**DO:**
+- Run `./gradlew test` or `./gradlew build`.
+- If checksum mismatch: `flyway.repair()` (dev/test only) then re-run.
+
+**DO NOT:**
+- Enable auto-repair in production.
+
+**Verify:**
+- [ ] Build/test succeeds with `ddl-auto=validate`.
+
+**Output:** Test/build result and any repair action.
+
+---
+
+# Output Contract
+
+Return exactly:
+1. **Migration File:** path + filename
+2. **Schema Change Summary:** what changed + backfill (if any)
+3. **Safety Notes:** NOT NULL pattern / repair usage / profile scope
+4. **Verification:** tests or build command run
+
+---
+
+# Common Anti-Patterns (MUST AVOID)
+
+## ❌ Anti-Pattern 1: Editing an applied migration
+
+**DON'T:**
+```sql
+-- ❌ Editing an already-applied migration
+ALTER TABLE trade_item ADD COLUMN net_payload_weight DECIMAL(19,2);
+-- (later edited to add IF NOT EXISTS)
+```
+
+**✅ CORRECT:**
+```sql
+-- ✅ Add a new migration file instead
+ALTER TABLE trade_item ADD COLUMN IF NOT EXISTS net_payload_weight DECIMAL(19,2);
+```
+
+**Consequences:**
+- Flyway checksum mismatch and blocked boot.
+- Divergent schemas across environments.
+
+## ❌ Anti-Pattern 2: Using `ddl-auto=update`
+
+**DON'T:**
+```yaml
+spring:
+  jpa:
+    hibernate:
+      ddl-auto: update  # ❌ breaks migration discipline
+```
+
+**✅ CORRECT:**
+```yaml
+spring:
+  jpa:
+    hibernate:
+      ddl-auto: validate  # ✅ schema managed by Flyway
+```
+
+**Consequences:**
+- Untracked schema drift.
+- Non-reproducible environments.
+
+## ❌ Anti-Pattern 3: Forcing NOT NULL without backfill
+
+**DON'T:**
+```sql
+ALTER TABLE trade_item ADD COLUMN net_payload_weight DECIMAL(19,2) NOT NULL;
+```
+
+**✅ CORRECT:**
+```sql
+ALTER TABLE trade_item ADD COLUMN net_payload_weight DECIMAL(19,2);
+UPDATE trade_item SET net_payload_weight = weight - COALESCE(weight_loss, 0);
+ALTER TABLE trade_item MODIFY COLUMN net_payload_weight DECIMAL(19,2) NOT NULL;
+```
+
+**Consequences:**
+- Migration fails on existing data.
+- Partial deployment rollbacks.
+
+---
+
+# Summary Checklist
+
+## Migration File:
+- [ ] New migration file created (no edits to applied files)
+- [ ] Filename follows `VYYYYMMDD__short_description.sql`
+- [ ] SQL is idempotent where possible
+
+## Data Safety:
+- [ ] Backfill included for NOT NULL changes
+- [ ] No destructive schema changes without explicit approval
+
+## Environment:
+- [ ] `ddl-auto=validate` remains unchanged
+- [ ] Auto-repair only in dev/test profiles
+
+**If ANY item is unchecked, schema drift or startup failures may occur.**
+
+---
+
+# Output Expectations
+
+When this skill is active, you MUST:
+
+1. State the migration filename and path.
+2. Explain the backfill/constraint sequence if NOT NULL is involved.
+3. Call out any repair action and profile scope.
+
+**Before writing code:**
+- Confirm whether a baseline migration exists for clean DBs.
+
+**When making changes:**
+- Never modify existing migration files.
+- Keep `ddl-auto=validate` in committed configs.
+
+**NEVER:**
+- Enable auto-repair in production.
+- Commit hardcoded DB credentials.